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UNITED STATES OF AMERICA. 



Physiology Primer 



PRIMER 



PHYSIOLOGY 



HYGIENE 



A TEXT-BOOK FOR PRIMARY CLASSES, WITH SPECIAL REF- 
ERENCE TO THE EFFECTS OF STIMULANTS AND 
NARCOTICS ON THE HUMAN SYSTEM 



BY 



WILLIAM THAYER SMITH, M.D. 

AUTHOR OF "THE HUMAN BODY AND ITS HEALTH" 



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Copyright, 1885, by 
IVISON, BLAKEMAN, TAYLOR, & COMPANY 

PUBLISHERS 
NEW YORK AND CHICAGO 



V 



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PREFACE. 



In studying the body, it is very desiraole that 
the scholar should, as far as possible, see and han- 
dle the parts described. Children especially can 
learn much more readily in this way than from 
any description. A dissection of a cat or dog or 
rabbit, illustrating the lessons, will make the text 
clear, and fix the essential facts in the mind. 

Or, if this can not be done, pieces of muscle and 
of cartilage, joints and bones, a heart, the lungs, 
a liver, an eye, and other organs, can be obtained 
from the butcher, to serve the same purpose. 

The apparatus mentioned in illustration of the 
action of organs — the bellows, the syringe, and 
others that may occur to the teacher — should be 
shown. 

Models and plates are also valuable. A few 
clear ideas of the structure and functions of the 



PREFACE. 



body will be worth much more to the children 
than many details imperfectly understood. 

On the subject of stimulants and narcotics, I 
have endeavored to make no statements which are 
not susceptible of positive proof, and to present 
only facts which children are capable of appreciat- 
ing. Much more might be said which does not 
come within the province of such a work as this. 

WILLIAM THAYER SMITH. 
Hanover, N.H., May 1, 1885. 



CONTENTS. 



CHAPTER I. 

PAGE 

Introduction 9 

Anatomy, Physiology, Hygiene. 

CHAPTER II. 

The Body 11 

Sect. I. Divisions of the Body. — Sect. II. The Skin. Perspi- 
ration. The Hair. Sebaceous Glands. The Nails. Care of 
the Skin. Bathing. Things to be avoided. Effects of Alcohol 
and Narcotics. 

CHAPTER III. 

The Muscles 24 

Sect. I. What Muscle is. What Muscle does. Walking. Ten- 
dons. How Muscle contracts. — Sect. II. Exercise. Expres- 
sion of the Face. Things to be avoided. — Sect. III. Effects 
of Alcohol and Tobacco. 

CHAPTER IV. 

The Heart and Blood-vessels 35 

Sect. I. What the Blood-vessels are. Arteries. Capillaries. 
Veins. The Heart. A Journey through the Heart and 
Blood-vessels. Action of the Heart. Effects of Alcohol and 
Tobacco. 

CHAPTER V. 

The Blood. — Wear and Repair. — The Lymphatics ... 50 
Sect. I. Amount of Blood. Corpuscles. Contents of the Blood. 
How Waste Matter goes out. Lymphatics. Painting. Purity 
of the Blood. Effects of Alcohol and Tobacco. 

5 



CONTENTS. 



CHAPTER VI. 

PAGE 

Food and Water. — Stimulants and Narcotics 60 

Sect. I. Nourishment. Animal and Vegetable Food. Cooking. 
Water. Eating and Drinking Habits. — Sect. II. What a 
Stimulant is. Tea and Coffee. Opium. Tobacco. Alcoholic 
Drinks. 

CHAPTER VII. 

Digestion. — Absorption 76 

Sect. I. The Inside of the Body. What Digestion is. The 
Teeth. Mastication. The Stomach. The Bowels. The Liver. 
The Pancreas. — Sect. II. What Absorption is. Dyspepsia. 
— Sect. III. Care of the Stomach. — Sect. IV. Effects of 
Alcohol and Tobacco. 

CHAPTER VIII. 

Respiration. —The Voice 95 

Sect. I. Air. The Lungs. The Trachea. The Nose. The 
Larynx. The Vocal Cords. The Bronchial Tubes. Breath- 
ing. Color of the Blood. — Sect. II. Effects of Alcohol and 
Tobacco. 

CHAPTER IX. 

The Nervous System. — The Eye. — The Ear 108 

Sect. I. The Brain. The Spinal Cord. Action of the Nervous 
System. Paralysis. — Sect. II. The Eye. Description of its 
Parts. Action of the Eye. Care of the Eyes. — Sect. III. 
Description of the Ear. — Sect. IV. Effects of Alcohol and 
Tobacco. 

CHAPTER X. 

The Framework 130 

Sect. I. The Vertebrates. Description of the Bones. — Sect. II. 
Joints. Different Kinds of Joints. Parts of a Joint. — Sect 
III. Structure of Bone. — Sect. IV. Care of the Frame. — 
Sect V. Effects of Alcohol and Tobacco. 

Glossary 141 

Index t 143 



LIST OF ILLUSTRATIONS. 



Fig. Page 

1. Skin of the Palm (magnified), showing Ridges and Pores . 14 

2. Sweat-gland, with small Blood-vessels surrounding it . . 15 

3. Vertical Section of the Skin, showing Roots of Hairs . . 16 

4. Muscles of the Back 25 

5. Biceps Muscle 26 

6. Muscles and Tendons 28 

7. The Arterial System (colored) 33 

8. Capillary Plexus (magnified) 36 

9. Diagram of a Section of the Heart, with Blood-vessels . . 37 

10. Representation of the Circulation of the Blood 39 

11. Semilunar Valves partly closed 41 

12. Red Corpuscles of Human Blood (400 diameters) 52 

13. Superficial Lymphatics of the Arm 55 

14. The Internal Organs 78 

15. The Lower Jaw and Teeth 79 

16. Back Tooth sawed in two 80 

17. Salivary Glands 82 

18. Section of the Stomach 84 

19. The Liver and other Organs of Digestion 86 

20. The Gills of an Eel 95 

21. The Heart and Lungs 97 

22. The Larynx 99 

23. Section of the Lungs 101 

24. Bronchial Tubes and Air-cells (magnified) 102 

25. The Chest 103 

26. General Representation of the 'Nervous System .... 109 

27. Half of the Brain, and Upper End of the Spinal Cord . . Ill 

28. Nerves of the Fore-arm and Hand 113 

29. Lachrymal Apparatus 119 

30. The Eye 120 

31. The Eyeball and Optic Nerve 121 

7 



LIST OF ILLUSTRATIONS. 



Fi«. Page 

32. The Ear 123 

33. The Skeleton 128 

34. The Backbone, sawed in two, lengthwise 129 

35. A Vertebra 130 

36. The Skull 131 

37. The Upper Limb 132 

38. The Lower Limb 133 

39. Joints of. the Skull 134 

40. The Hip-joint 135 

41. The Shoulder-joint 136 

42. Section of the Thigh-bone 137 



PHYSIOLOGY PRIMER. 



CHAPTER I. 



INTRODUCTION. 

Sect. L — 1. When we were very young chil- 
dren, Ave did not need to know much about our 
bodies. Our parents took care of them. They 
managed our eating and drinking and sleeping. 
They clothed us, and tried to keep us in good 
health. 

As we grow older, we can take more care of 
ourselves. But we can not take care of our bodies 
properly unless we know something about them. 

We need to know what they are made of; what 
becomes of the food we eat; what things are good 
to eat and drink, and what are bad ; Avhy we 
breathe ; what the heart beats for. 

All this knowledge is called Anatomy and 
Physiology. 



10 PHYSIOLOGY PRIMER. 

2. The body is like a clock, with its wheels, and 
its spring, and its hands, and its ticking. If we 
take the clock to pieces, to see what it is made of, 
that is like the study of Anatomy. Just so the 
bodies of animals and men have been examined, 
to see what they are made of. If we set the clock 
a-going, and watch it to see how it ticks and 
strikes, and turns its hands, that is like the study 
of Physiology. Just so learned men spend a great 
deal of time in watching animals and men, to see 
how they move and eat and breathe and feel. 

When we have learned these things about our 
bodies, we shall know how they should be taken 
care of in order to keep them in health. This 
knowledge is called Hygiene. 

3. Many grown people are very ignorant of 
these things. They abuse their bodies, and wear 
them out in various ways. Drinking intoxicating 
liquors, and smoking or chewing tobacco, are 
among the most common ways. 



QUESTIONS. 

Sect. I. — 1. What is Anatomy ? Physiology ? 

2. What may the body be compared with ? What is Hygiene ? 

3. Are we all acquainted with our own bodies ? Mention a com- 
mon way of abusing the body. 



THE BODY. — THE SKIN. 11 



CHAPTER II. 



THE BODY. 

Sect. I. — 1. When we look at the body of a 
man, we notice these things : — 

(I.) It is made of several parts; namely, the 
head and neck, the trunk, the upper limbs, the 
lower limbs. 

The upper limbs are divided into the arm (from 
shoulder to elbow), the fore-arm (from elbow to 
wrist), and the hand. 

The lower limbs are divided into the thigh (from 
hip to knee), the leg (from knee to ankle), and 
the foot. 

(2.) If we draw a line from the top of the head 
down on the backbone, we shall divide the body 
into halves, which are just alike. Each half has 
an eye and an ear, and an arm and a leg. True, 
we have but one nose and one mouth; but nose 
and mouth have two sides, which are alike. 

(3.) The whole body is covered by the skin. 

THE SKIN. 

Sect. II. — 1. The skin is soft and smooth and 
elastic. It fits perfectly, and yet is never tight, as 



12 PHYSIOLOGY PRIMER. 

new clothes sometimes are. It is about one-tenth 
of an inch thick, and it has two layers. When 
we raise a blister, the top layer, called the cuticle, 
is lifted up by the water which gathers under it. 
When we fall, and scrape the skin off, it is gener- 
ally only this same top layer that we have scraped 
off. The red, sore surface which is left, is the deep 
layer, or cutis. If we really scrape away the whole 
thickness of the skin, it is a serious injury. After 
a blister, the skin will heal, and look just as it did 
before. But, if both layers of the skin are torn or 
cut out, a scar will remain. 

2. A scar is a piece which nature puts in to 
patch a torn skin. Like the patch on a boy's 
trousers, it never looks exactly like the rest of the 
skin. That is because it is not exactly like it. It 
is not real skin. One peculiarity of a s.car is, that 
it keeps shrinking for a long time. If a child gets 
a deep burn on his neck, the scar will often shrink 
so much that it will draw his head to one side, and 
give him a wry neck. If the burn is under his 
arm, the scar may draw his arm down so that he 
can not raise it far from his side. On his hand, it 
may prevent him from straightening his fingers. 

3. It is very important when a deep burn, or 
any other injury that takes out a part of the skin, 
is healing, to have it properly attended to. By 



PERSPIRATION. 13 



care, the scar may be kept from drawing too 
much. 

4. Dandruff is from the outer layer of the skin 
on the head. When the scalp is dry, these little 
scales come off in great numbers. Just such 
scales, only smaller, are coming off all the time 
from every part of the skin. They are rubbed off 
with each movement that we make. But they are 
so fine that we do not see them. In this way the 
skin is continually wearing off; and, if it did not 
grow, it would soon be all worn away. But it 
grows down in the deep layer as fast as it wears 
off on the surface. 

PERSPIRATION. 

5. If you touch the face of a person sick with 
a fever, you will find that it is hot and dry. The 
skin of a well person has a different feeling. It 
is moist. When the air is very hot, or you have 
been playing hard, you can see the moisture stand- 
ing in drops, or running down in streams. 

We call this perspiration, or sweat. Where 
does it come from? 

6. On the ends of your fingers, you can see that 
the surface of the skin is all in ridges, with furrows 
between. With a strong magnifying-glass, these 
ridges would look as they do in the figure (Fig. 1) . 



14 



PHYSIOLOGY PRIMER. 




You would see on the ridges little holes, which are 
represented by the black dots in the figure. Just 

such little holes are in the 
skin all over the body. We 
call them pores. There are 
as many as 2,500,000 of them. 

7. The pores are the 
mouths of little pits, or wells, 
which are called the sweat- 
glands. 

These wells are tubes about 
one-fourth of an inch long, 
which run down nearly to 
the under-surface of the skin, 
Ridges m the skin of the Paim. anc [ there end in a coil. 

The Black Spots are the Pores. 

8. The sweat is constantly 
rising in these tubes, and flowing over on the sur- 
face. Ordinarily it dries off immediately, and we 
can not see it. When we are very warm, it comes 
faster than it can dry ; and we feel and see it. 

9. But where do these tubes get the sweat ? By 
examining with the microscope, it has been found 
that the coils at the bottom of the tubes are all 
covered with a network of very small blood- 
vessels. The blood is partly water; and, as it flows 
through these little vessels, some of the water 
soaks through their walls, and through the walls 



Fig. I. 



THE HAIR. 



15 



of the sweat-gland; and so these glands are con 

tinually filling, and flowing 

over. 

The sweat-gland is like a 
spring in which water is al- 
ways bubbling up from streams 
down under-ground. 

10. Since each one of the 
tubes is about one-fourth of an 
inch long, and there are about 
2,500,000 of them, you can 
easily estimate the length of 
the tube that would be made if 
they were all joined in one. 
More than a pint of water passes off through the 
pores, from the body of a man, in a day. 




Fig. 2. 

Sweat-Gland , with small blood- 
vessels surrounding it. 



THE HAIR. 

11. A dog or a horse has hair all over his skin. 
So has a man ; but, on the most of his body, it is 
so short and thin that you can scarcely see it. 
The reason for this is plain, when we remember 
that man has skill and hands to clothe himself, 
and the dog and the horse have not. Therefore, 
Mother Nature, who takes good care of even her 
dumb children, makes the hair grow thick to keep 
them warm. She did not intend that men should 



16 



PHYSIOLOGY PRIMER. 



cover their heads as they do their bodies, for eyes 
and ears and nose and mouth must be kept open. 
So she gave us long hair on our heads to protect 
them in part. 

Hair is beautiful as well as useful. Each hair 
has its root at the bottom of a tube, which runs 
down from the surface to the under side of the 
skin. 

SEBACEOUS GLANDS. 

12. Besides the sweat-glands, there are other 
glands in the skin, called sebaceous glands. 

They are little sacs, 
with a tube leading 
from them. They 
give out an oily fluid. 
On the face, they are 
rather large. Some- 
times they get full of 
the fluid, which be- 
comes thick, and then 
turns black. When 
these black spots are squeezed, their contents come 
out. They look like worms, and are often called 
worms. 

13. But most of the sebaceous glands open into 
the tubes from which the hairs grow. They dis- 
charge their oil about the roots of the hair. This 




Fig. 3. 

SECTION OF THE SKIN, SHOWING ROOTS 
OP HAIRS. — 1. Muscles attached to the 
hair-sac. 2. Sebaceous glands. 



THE NAILS. — WHAT THE SKIN IS FOB. 17 

makes the hair soft and glossy. The oil spreads 
over the surface of the skin also, and helps to 
keep it smooth and soft. When the scalp is un- 
healthy, these little glands do not work, and the 
hair becomes dry and brittle. 

THE NAILS. 

14. The nails, like the hairs, grow out of the 
skin. They make the ends of the fingers firm, so 
that we can pick up small things, and hold them 
better. 

15. The nails are all the time growing ; and, if 
one is torn out, a new one will grow, provided 
that the red bed of skin under it, from which it 
grows, is not also torn away. 

The habit of biting the nails ought always to 
be avoided. Fingers on which the nails are bitten 
to the quick look badly, and are less useful than 
others. 

WHAT THE SKIN IS FOR. 

16. (7.) The skin is a protection to the parts 
under it. It is elastic and tough. A strong man 
can sometimes split a board with his fist without 
breaking the skin. 

We sometimes have to handle things that are 
poisonous. If our skin is whole, we will not be 
hurt. But, if we have a scratch or cut on our 



18 PHYSIOLOGY PRIMER. 

hands, we should be very careful how we let any 
thing poisonous touch it. 

(2.) The skin keeps the body warm. 

(3.) The skin makes a delicate and beautiful 
covering. 

(4.) The skin gives off waste matters from the 
body. 

You remember about the sweat-glands, — how 
the water passes from the blood into them, and 
out on the surface of the body. But sweat is not 
all water. It contains also salt and other sub- 
stances which the body needs to get rid of. These 
amount to two or three spoonfuls in a day. If the 
skin does not carry this off, we can not be well. 

(5.) The skin regulates the heat of the body. 

BODILY HEAT. 

17. The body is a kind of walking stove, which 
is making heat all the time. A number of cattle 
together will keep a cold barn warm, and a num- 
ber of people in a room will make it very hot in 
warm weather. 

The food that we eat is the fuel, and the life in 
us is the fire. When the fire is out, the stove is 
cold. When the life is out, the body is cold. Now, 
the heat that is made is kept in by the skin and 
by the clothing. 



BODILY HEAT. 19 



18. But suppose we are too warm. Then the 
skin, instead of keeping in heat, lets it out ; and 
it does it in this way : — 

If our faces are hot, and we wet them, and let 
them dry in the air, it cools them. When water 
dries off from any thing, it always cools it. If we are 
too warm, the sweat-glands go to work actively, 
and the water wells up fast on the surface, and 
dries off. This makes us cooler ; and, when we are 
cool enough, the sweat-glands work more slowly 
again. 

19. Some men are foolish enough to drink 
whisky, when it is hot, to make them cool ; and, 
when it is cold, they drink it to make them 
warm. 

They might better trust to the natural action of 
the healthy skin, which whisky interferes with. 

20. In cold weather we eat more food, and we 
wear thicker clothing. Clothing does not make 
heat, but it keeps in the heat we have. Besides 
that, we are obliged to keep fires burning, in order 
to be comfortable. We are not as independent as 
the animals, whose bodies can make heat enough 
to endure winter without fires. 

21. The temperature of the blood is always 
about 100° Fahrenheit when we are well. It 
makes little difference whether the air about us is 



20 PHYSIOLOGY PRIMER. 

warm or cold. In the African and the Green- 
lander it is the same. 

When we have a fever, it is higher, and may 
reach 106° or 107° Fahrenheit. 

CARE OF THE SKIN. 

22. Since the skin has such important work to 
do, we ought to take good care of it. We are not 
likely to tear our skins, or burn them, or wear 
holes in them, — as we do with our clothes, — if 
we can help it. Nature has filled them full of 
delicate little nerves, which give us great pain if 
we do any such thing. We are pretty careful not 
to hurt them, or to let any one else hurt them. 
But we may neglect them. 

23. It is bad for the skin to wear too thick 
clothing. It keeps it wet with perspiration, and 
softens and weakens it. 

It is bad for the skin to stay too much in hot 
rooms. The skin needs fresh air to make it vig- 
orous. 

BATHING. 

24. The skin should be thoroughly washed 
often. A daily bath is an excellent thing. 

Bathing keeps the pores and the sebaceous 
glands open. The rubbing by which we dry it 
makes the blood flow through it, and makes it soft 



THINGS TO BE AVOIDED. 21 

and pliable. The cool water rouses it, and makes 
it active. If we bathe often, we shall not be likely 
to catch cold. We catch cold by getting the skin 
chilled by damp air or water. By bathing and 
rubbing, the skin becomes strong, so that it is 
not as easily chilled when we are in a draught, 
or wet our feet. People have been cured of many 
diseases by simply bathing and rubbing the skin. 
It is one of the very best ways to prevent disease. 
Bathing in salt water is more refreshing than 
bathing in fresh water. The salt stimulates the 
skin. 

THINGS TO BE AVOIDED. 

25. When you are perspiring a good deal, do 
not sit down on damp ground, or in a draught of 
air. It may give you a cold to chill your heated 
skin so suddenly. 

For the same reason, do not go into cold water 
when you are heated from play. Cool off first. 

Do not bathe directly after eating. 

Never stay in the water until you are chilled 
through. It may injure you seriously. 

EFFECTS OF ALCOHOL AND NARCOTICS. 

26. A clear complexion is a great beauty. Any 
thing that will destroy it should be avoided if pos- 
sible. The use of alcoholic liquors reddens the 



22 PHYSIOLOGY PRIMER. 

nose, and often mars the face with blotches and 
pimples. 

2H. Tobacco-using boys acquire a sallow, lifeless- 
looking skin, which represents the condition of 
their whole system. 



QUESTIONS. 

Sect. I. — 1. What parts make up the body ? Where is the 
thigh? the fore-arm? 

How may the body be divided into parts which are just alike? 
What covers the body ? 

Sect. II. — 1. Describe the skin. What happens when we raise 
a blister ? when we scrape the skin off ? 

2. What is a scar? What danger in a large scar? 

3. What should we take pains to prevent when the skin is de- 
stroyed in any part ? 

4. What is dandruff? How does the skin wear off? Why does 
it not wear out ? 

5. What is perspiration ? 

6. What are the pores ? How many of them are there ? 

7. Describe the sweat-glands. 

8. How do the sweat-glands act ? 

9. Where does the sweat come from ? 

10. How many sweat-glands are there? How long a tube 
would they make if all were joined in one? 

11. W T hy has not man as much hair as the lower animals? 
What is the use of hair ? 

Where are the roots of the hair? 

12. What is a sebaceous gland? What does it give out? 

13. W T hat have the sebaceous glands to do with the hair? 

14. What do the nails grow from? What are they good for? 



QUESTIONS. 23 



15. Will a nail grow again if it is torn off? 

16. Uses of the skin. Name the first mentioned ; the second; 
the third ; the fourth ; the fifth. 

17. How is the body kept warm? 

18. How is the body cooled when too warm? 

19. Is whisky good to keep men warm or cold ? 

20. How do we keep our heat in cold weather? 

21. What is the temperature of the blood? Is it the same in 
all men? How does it change in a fever ? 

22. How does Nature keep us from injuring our skins? 

23. What is bad for the skin? 

24. What is the effect of bathing the skin? How do we catch 
cold? 

25. Name some things to be avoided. 

26. How may the use of alcohol affect the skin? 

27. How may the use of tobacco affect the skin? 



24 PHYSIOLOGY PRIMER. 



CHAPTER III. 



THE MUSCLES. 

Sect. I. — 1* We have taken a general view of 
the outside of the body, and studied its covering. 
We have next to examine the parts beneath. 

If I ask you what we shall find if we take off 
the skin of an animal, you will probably answer 
flesh. 

If I ask you what flesh is, you will tell me that 
it is a part of an animal which is red and soft and 
elastic, and that it is good to eat. 

You perhaps do not know that this flesh, which 
is served up as roast beef, mutton, and other meats, 
is the muscle of the animal. While he is living, 
it enables him to move and work. When he is 
killed, it is our food. 

2. If you grasp your fore-arm just below your 
elbow, and then double your fist tightly, you will 
feel your fore-arm swelling, and growing hard. 

All boys know how to bend the elbow, and feel 
the lump rising on the front of the arm. 

It is muscle that swells and hardens under the 
skin. 



TIIE MUSCLES. 



25 



3. Our flesh is not all one mass of muscle, but 
it is made up of many muscles bound together. 




Fig. 4. 

Muscles of the Back. 



Muscles are of different shapes. Some of them 
are flat, like a piece of cloth. Flat muscles are 



26 



PHYSIOLOGY PRIMER. 



spread out over the trunk of the body. Some 
of them are long and slender. The sartorius or 
tailor's muscle, which is in the thigh, is about two 
feet long. Some of them are shaped like a spindle 
full of thread. The smallest muscle in the body 




Fig. 5- 

1. BICEPS MUSCLE. The dotted lines indicate the changed shape of the biceps 
when the fore-arm is drawn up. 

is called the stapedius. It is in the ear, and is 
not more than one-sixth of an inch long. 

4. Most of the muscles are attached to a bone 
at each end. When they swell and shorten, they 
draw one of these bones nearer to the other. 
When you lay your hand on your arm, and feel 
the muscle in it swell, it is drawing the fore-arm 
toward the shoulder. This muscle, called the 
biceps, is attached to a bone of the shoulder above, 
and to a bone of the fore-arm below. 



WALKING. 27 



It is by the muscles acting in this way that we 
make all our movements. 

WALKING. 

5. For example, let us see how we walk. Stand 
with your feet together. Begin slowly to walk, 
and see what you do. First you lean a little, so 
as to throw your weight on either your right or 
your left foot. Let it be the left this time. Then 
the muscles of your thigh contract, and lift your 
right foot from the ground, and carry it forward. 
All this time your weight is resting on your left 
foot. When you have carried your right foot far 
enough forward, you let it come down on the 
ground. Then both feet are on the ground, the 
right being some distance ahead of the left. Next 
the muscles of the calf of your left leg shorten; 
and that raises your left heel from the ground, 
and throws your whole body forward on your 
right foot. Then the muscles in your left thigh 
contract, and lift the left foot clear of the ground; 
and it swings forward by its own weight — like 
a pendulum — until it is ahead of the right foot, 
when it is planted on the ground. So each foot 
in its turn swings ahead of the other. 

The muscles mentioned are not the only ones 
engaged in walking. A great many muscles take 



28 



PHYSIOLOGY PBIMEB. 



Muscle. 



part. These are the principal ones. By laying 
your hand on your thigh or calf, you can feel 
them harden as you step. 

TENDONS. 

6. Most of the muscles have a 
tendon at one or both ends. A ten- 
don is a strong, tough white cord 
or band. It may be round or flat ; 
and it does not stretch, as muscle 
does. Any boy whose parents 
kindly let him have the drumstick 
when there is chicken for dinner, 
can find the tendons in it. They 
are not good to eat, but they are 
very good to fasten a muscle to a 
bone. 

7. The largest tendon is the 
tendon of Achilles, the thick cord 
w T hich is fastened to the heel. It 
is at the end of two big muscles 
that make the calf. You can 
easily find out why it is called the 

tendon of Achilles. The story is too long to tell 
here. 

The tendons of the muscles of the fore-arm can 
be seen and felt just above the wrist. 




Tendon 



Fig. 6. 

Muscles and Tendons. 



TWO KINDS OF MUSCLE. 29 

TWO KINDS OF MUSCLE. 

8. The muscles on the outside of the body con- 
tract when we will. They are called voluntary 
muscles. But there are other muscles, which do 
not obey our wills. They are called involuntary 
muscles. These are chiefly inside of the body. 
They are in the walls of the stomach and bowels 
and of the breathing-tubes and blood-vessels. 
The heart itself is made of this kind of muscle. 
These muscles work of themselves, without asking 
our permission. The Creator has made us so that 
we can move our bodies as we please. But the 
heart and other involuntary muscles he put in us 
to do a certain work by his direction. We can 
help or hinder them, but we can not control them 
directly by our wills. 

It is much better for us that it is so. The work 
of the involuntary muscles is necessary for the 
continuance of our lives. They are like good ser- 
vants that do it for us without troubling us to 
look after them. 

HOW MUSCLE CONTRACTS. 

9. We do not know how muscle shortens when 
we wish it to. We know that it does so, but we 
can not explain it. 



80 PHYSIOLOGY PBIMEB. 

EXERCISE. 

Sect. II. — 1. All parts of the body were made 
to be used. Prisoners grow pale and thin and 
weak for want of exercise. If your leg gets lame, 
so that you can not use it, in a little while you 
will find it growing softer and smaller than the 
other one. 

2. The muscles make nearly half of the body, 
so they need a good deal of exercise. The plays 
which are natural for children are good for them. 
They make the muscles strong and active. 

3. One reason why exercise is good for the mus- 
cles is, that it makes the blood flow faster through 
them. If the blood is cut off from a muscle, it 
gets numb, and will not work. Plenty of blood 
makes it grow. 

4. Another reason is, that, when we exercise, 
we breathe fast, and get a good deal of oxygen 
into our blood. Such blood gives more life to the 
muscles. 

5. If we wish to have well and active bodies, 
we must be willing, not only to play, but also to 
work, with our muscles. 

EXPRESSION OF THE FACE. 

6. A very important set of muscles is in the 
face. They are attached to the skin, and by their 
action give various expressions. 



EFFECT OF ALCOHOL AND TOBACCO. 31 

Those expressions which are most frequently on 
the face, finally become fixed there. So the face 
shows the state of the mind, and one who desires 
to have a beautiful face must be careful to keep a 
kind and happy temper. 

THINGS TO BE AVOIDED. 

7. We should not try to do things that are too 
hard for our strength. 

Neither should we try to keep up an exercise 
until we are exhausted. By running, or jumping 
rope, too long, children may be seriously injured. 

EFFECT OF ALCOHOL AND TOBACCO. 

Sect. III. — 1. The tendency of alcohol is to 
cause muscle to change into fat. Men who drink 
a good deal of it may look very large and strong 
when they are really weak. Their muscles are 
not hard, but soft and fatty. 

Men who are training for a race do not use alco- 
hol and tobacco, because they know their muscles 
will be weakened by them. 

2. It is a fine thing for a boy or a man to have 
strong muscles. 

He can enjoy himself, and help others better, 
for it. It is not a fine or a manly thing to have 
the sallow face, and thin legs and arms, that are 



32 PHYSIOLOGY PRIMER. 

likely to belong to boys who smoke cigarettes or 
cigar-stumps. 

— • m • 

QUESTIONS. 

Sect. I. — 1. What lies beneath the skin? 
What is flesh? 

2. What swells and hardens when we bend our elbows ? 

3. What shapes have muscles? Where is the longest muscle in 
the body? W r here is the shortest? 

4. What do muscles do? W r hat are they attached to? What is 
the biceps muscle attached to? 

5. Describe the process of walking. 

6. What is a tendon? What is its use? 

7. Where is the tendon of Achilles? Why is it so named? 

8. What are the two kinds of muscle called? 
What is the difference between them? 

Where are the involuntary muscles chiefly found? 

9. Do we know how muscle shortens ? 

Sect. II. — 1. W T hat happens to a muscle if we do not exercise 
it? 

2. How much of the body is muscle? 

3. Give a reason why exercise is good for the muscles. 

4. Another reason. 

5. W r hat must we do to have well and active bodies? 

6. What gives expression to the face? 
How may we cultivate beauty of face ? 

1. In exercising, what caution is to be observed? 

Sect. III. — 1. What is the effect of alcohol on muscle? Do 
athletes in training use it? 

2. Does using tobacco make a boy manly, or unmanly ? 




Fig. 7. 

The Arterial System. 



THE HEART AND BLOOD-VESSELS. 35 



CHAPTER IV. 



THE HEART AND BLOOD-VESSELS. 

Sect. I. — 1. If you cut yourself, or even prick 
yourself with a fine needle, blood will flow. 

In examining the flesh of an animal, after taking 
off the skin, we find it to be full of blood. 

In almost every part, even in the bones, there is 
blood. 

If we look very carefully at the flesh with a 
microscope, we find that the blood is not in it in 
the same way that water is in a w x et sponge. It is 
filled with little tubes, — some of them so small 
that you can not see them with the naked eye, 
and some larger, — and the blood is contained in 
these tubes. They are so close together, that, if 
you make never so small a cut, you are sure to 
cut some of them, and let the blood out. These 
tubes are called blood-vessels. 

2. The blood-vessels are arteries, capillaries, 
and veins. 

3. The arteries are all, except one, branches of 
a large tube that comes out of the heart. This 
tube, which is called the aorta, runs up a little 



36 



PII YSIOL OGY PRIMER. 



way, and gives branches to the head and arms, and 
then goes down by the backbone, giving branches 
to the trunk of the body and the parts inside. 
Finally, it divides into two tubes, that run down 
through the legs to the feet. 

4. The branches that come off from this great 
tube keep dividing and dividing, until, finally, the 
branches become so small that they are called 
capillaries, which means " like hairs." 

If these capillaries were laid side by side, it 
would take 3,000 of them to cover a space an 

inch wide. 

There are a great many of 
them, and they make a net- 
work as close as any spider's 
web that you see in the grass 
on a summer morning. They 
are thick in almost everv 
part of the body. 

5. The vessels, after dividing into capillaries, 
soon unite to form veins. These veins join together, 
to form larger ones, just as streams join, to form 
larger streams and rivers. Finally, all are united 
in two great veins which open into the heart. 
The blood-vessels, which lie just beneath the skin, 
and which swell and look purple when you press 
them, are veins. 




Fig. 8. 

Capillary Plexus magnified. 



THE HEART. 



37 



THE HEART. 

6. The heart is in the breast, and lies toward 
the left side. If you begin at your collar-bone, 
on the left side, and count the ribs downward, you 
will find the point of the heart beating just under 
the fifth rib. 

It is shaped like a pear. It is made of muscle. 



Pulmonary artery. 
Vena cava superior. „ \ 



Pulmonary veins. <*:! " 

Right auricle _ 

Tricuspid valve. }x 

Vena cava inferior. ... 

w 



Right ventricle. /'' 



Aorta. 




.Pulmonary artery. 

■y Pulmonary veins. 

Left auricle. 
Mitral valve. 

Left ventricle. 



Aorta. 

Fig. 9. 

The Chambers of the Heart. 



It is hollow, and is divided in the middle into two 
halves, which are entirely separate from each other. 
Each half is divided into two chambers, which are 
connected by an opening. The two chambers on 
the right side are called the right auricle and the 
right ventricle. The two chambers on the left side 
are called the left auricle and the left ventricle. 



PHYSIOLOGY PRIMER. 



7. * Imagine yourself small enough to get inside 
the heart, and take a journey through the blood- 
vessels, to find out more about them. Start in the 
right auricle. If you look about you, you will find 
that it has thin walls, and has a lining smooth as 
glass. You will see three large openings in the 
walls. Two of them are the openings of the two 
great veins that empty into the heart. The third 
is about an inch wide, and you pass through it 
into the right ventricle. This has thicker walls 
than the auricle. There is only one opening to 
let you out of it; and you pass through this, and 
find yourself in a great tube with the same smooth 
lining that the cavities had. You are out of the 
heart, and are in the pulmonary artery. 

Traveling through this artery, you soon come 
to a place where it divides into two, — one going 
to the right lung, the other to the left. You may 
take which you choose. As you enter the lung, 
you find your passage-way constantly dividing 
into smaller ways. You find, too, that the walls 
of the tubes are growing thinner, but the same 
glossy lining continues. Finally, you get into a 
passage so narrow, that, if you are more than 3^ of 
an inch in size, you can not get through it without 

1 I am indebted, for the suggestion of the illustration following, to 
Professor Foster, Science Primer, Physiology, p. 52. 



THE HE Alt T. 



39 



squeezing. This is a capillary. You are glad 

when the passage grows a little larger, and you 

find yourself in a vein. This leads you into a 

larger vein, and this into a still larger one, until 

you are in one of the pulmonary veins ; and from 

that you plunge into another 

cavity. You have reached the 

heart again, and are in the left 

auricle. This, which is very 

much like the right auricle, 

opens into the left ventricle. 

Pausing in this cavity before 

you leave the heart once more, 

you will perceive that its walls 

are much thicker than those of 

the other cavities. Taking the 

only opening out of it, you 




Fig. 10. 

MAN.- 
6. Right 
ventricle, c. Pulmonary ar- 
tery, d. Capillaries of the 
lungs, e. Pulmonary veins. 
/. Left auricle, g. Left ven- 
tricle, h. Aorta, i. Capil- 
laries, k. Vein. 



enter another great tube, the circulation in 

. a. Right auricle. 

aorta. This is of about the 
same size as the pulmonary ar- 
tery, but its walls are thicker 
and stronger. As you pass on, 
you notice that there are many large tubes open- 
ing out of it. But you keep the main channel 
until at length you reach a point where it divides. 
Taking either of the two divisions, you move on 
down into the thigh, the leg, and the foot. All 



40 PHYSIOLOGY PRIMER. 

the while your tube has been growing smaller as 
it gave off branches. Soon you find yourself again 
in a capillary. But it is only a fraction of an inch 
long, and you are quickly through it, and are in 
a vein. Passing up by the same course by which 
you came, the vein grows larger and larger as 
branches join it. You traverse the leg and thigh, 
and, when you reach the back again, you are in 
one of the two great veins which open into the 
right auricle of the heart. There you find yourself 
resting after your long journey. 

8. As you rest, you think about two things that 
you have noticed. 

(1.) You noticed that you saw no openings out 
of the blood-vessels. There were a great many dif- 
ferent ways that you might take, but they all con- 
nected, like the paths in a park; and, though you 
might wander about a good while, you would 
always get back at last to the heart. 

(2.) You noticed, that, at many points in your 
journey, you passed through open gates, and that 
they always opened in the direction in which you 
were going. This would not have been so, if, when 
you started in the right auricle, you had gone 
directly into a vein, and so through the veins into 
the capillaries, and then through the arteries back 
to__the heart. If you had gone in that .direction, 



THE HEART. 



41 



you would have found that the gates opened to- 
ward you, and that if you happened to strike 
against them, or if there had been a crowd trying 
to get through with you, you w^ould have closed 
them against yourself. 

This shows you that it was intended that the 
blood should flow in the direction in which 
you went, — through the arteries first, and back 
through the veins. It could not flow the other 
way, because it would close the gates against it- 
self. 

These gates are called valves. They are made 
of thin membrane, and are more like curtains 
than gates ; but they are tough and strong, and fit 
so that they close the w r ay perfectly. 

They work like the valves in a pump, which 
allow the water to come up, but 
shut when the water settles back. 

The valve w r hich closes the 
opening between the right auricle 
and ventricle is called the tri- 
cuspid valve. The valves at the 
entrance of the pulmonary artery 
and the aorta are the semilunar 
valves. The valve between the 
left auricle and ventricle is the mitral valve. Be- 
sides these, there are valves all along the veins, 




Fig. II. 

Semilunar Valves partly- 
closed. 



42 PHYSIOLOGY PBIMER. 

though there are none in the arteries except the 
semilunar valves just mentioned. 

ACTION OF THE HEART. 

9. If you have a pretty good idea of the heart 
and blood-vessels from your journey, you can now 
learn what they do. 

We know, to begin with, that the heart and 
blood-vessels are full of blood. We know, also, 
that the blood is always moving through them, as 
rivers and streams are always flowing. We can 
even see it move in the blood-vessels which are in 
the thin web of a frog's foot, if we look at them 
with a microscope. We know, too, that it is 
always flowing in the direction which you took 
on your journey, — from the heart through the 
arteries and capillaries, and back to the heart 
through the veins. It is easy to find this out 
when an artery or vein is cut off. We can see 
which way the stream is running. We know, be- 
sides, that it could not flow the other way, on 
account of the valves. 

10. The heart and blood-vessels are not like 
lead pipes, that simply let the water flow through 
them. The heart is a live pump. It works itself. 
The blood-vessels stretch and contract, and so help 
the heart to keep the blood moving through them. 



ACTION OF THE HEART. 43 

11. If you lay your ear against any one's breast, 
you can hear and feel the heart beat. It begins to 
beat almost at the beginning of life, and keeps 
on until we die. The only rest it gets is a very 
short rest between the beats. But, as there are a 
great many beats in a day, of course there are 
a great many of these short rests. If they were 
all put together, it would make one long rest of 
eight hours in a day. But no other muscle does 
sixteen hours of constant work in twenty-four. 

12. The heart beats very fast in a baby, — as 
many as a hundred and twenty times in a minute 
if he is less than a year old. In a grown man, it 
beats about seventy times in a minute. "When we 
are excited, it beats faster and harder, sometimes 
so hard that it gives us distress. When we exer- 
cise, it beats fast. 

When we are well, we do not think any thing 
about our hearts, or even feel that they are in our 
breasts. 

13. What makes the heart beat, and what is it 
doing ? 

You remember that the heart is made of muscle. 
You remember, too, that muscle can shorten and 
thicken. If we could look through the breast 
at the heart, we would see, that, at every beat, it 
thickens and hardens, just as the biceps does when 



44 PHYSIOLOGY PRIMER. 

you bend your elbow. At the same time, it jumps 
a little, and its point hits the inside of the breast. 
Then it softens again for an instant before the next 
beat. 

14. Double your fist loosely, and suddenly 
tighten it, and you will make a motion somewhat 
like a heart-beat. Your fist, too, is of about the 
same size as your heart. Now, if you put your 
fist in a basin of water, and close and unclose it, 
the water will squirt out as you tighten your fist. 
That shows you what the heart does when it 
beats. It is full of blood ; and, when it contracts, 
it squirts the blood out into the pulmonary artery 
and the aorta. 

15. A common rubber syringe will show you 
how the heart works. The bulb of the syringe is 
the heart. The tube that goes into the water 
represents the great veins, and the other tube 
represents the aorta. Every squeeze you give the 
bulb is like a beat of the heart. 

16. You know, that, in such a syringe, the water 
goes only one way. If you put the wrong tube in 
the water, it will not go. That is because there 
are valves in the tubes that keep the water from 
going backward. Just so the blood goes only one 
way from the heart. The valves keep it from 
going the other way. 



THE PULSE. 45 



17. If you should fill the bulb and the tubes 
with water, and then join the ends of the two 
tubes together so that the water could not get 
out, but w r ould keep going around and around 
through the tubes and the bulb as you squeezed, 
you would have something a good deal like the 
circulation of the blood. 

THE PULSE. 

18. When you are sick, the doctor puts his 
finger on your wrist to feel your pulse. Under 
the end of his finger something beats, just as the 
heart beats against the chest, and almost at the 
same time. 

It is a small artery that he feels. When the 
heart beats, it forces blood into the arteries. They 
were nearly full before, but they can stretch like 
rubber. As the blood is forced in, they stretch 
and swell and rise up under the finger. A pulse 
can be felt in several places. If you look sharply, 
you can see a pulse in the neck often. It is the 
carotid artery that beats there. The pulse in the 
wrist is generally chosen, because it is the most 
convenient. 

19. By feeling the pulse, we may learn, among 
other things, — 

(i.) How fast the heart beats. If we have a 



46 PHYSIOLOGY PBIMEB. 

fever, it beats too fast. In some sicknesses it beats 
too slowly. 

(3.) How strongly it beats. If the heart is strong, 
the pulse w T ill be strong. If the heart is weak, 
the pulse will be weak. 

20. The blood flies quite swiftly through the 
large arteries. It moves more slowly through the 
capillaries. If an artery is cut, it w T ill spurt out 
in jets. If capillaries only are cut, it will ooze 
out in drops. If a vein is cut, it will flow out in 
a steady stream. 

EFFECTS OF ALCOHOL AND TOBACCO. 

21. When we see a man whipping a good horse 
who is going fast enough, w T e feel angry. Now, 
the heart is like a willing horse. When it is mak- 
ing its seventy beats in a minute, it is going fast 
enough. It is unnecessary and foolish to use any 
thing that will act as a whip does on a horse, and 
make it beat faster. That is just what alcohol 
does. If it is beating seventy times in a minute, 
a little alcohol will often make it beat seventy-four 
or seventy-five times in a minute. Four or five 
extra beats in a minute make a great many extra 
beats in a day. And all these extra beats are labor 
lost. They are using the strength, without doing 
a particle of good. 



EFFECTS OF ALCOHOL AND TOBACCO. 4< 

22. Alcohol, when used habitually, often in- 
jures the heart and blood-vessels. 

The heart it injures by changing its fibers partly 
into fat. The blood-vessels it injures by making 
them hard and brittle. 

Of course, a fatty heart can not be as strong 
as if it were all muscle, and it can not do its 
work as well. It is liable to stretch and wear out 
before its time. 

23. When the blood-vessels are brittle, a man is 
in danger of apoplexy. 

Apoplexy is a disease caused by the breaking of 
a blood-vessel in the brain. The person who has 
it becomes paralyzed in part or all of the body. 
He may become insensible, and die within a few 
days ; or he may get better, but remain paralyzed. 
He very seldom gets entirely w r ell. 

Young persons do not often have apoplexy, 
unless their blood-vessels are injured. The habit 
of drinking prepares the blood-vessels, and often 
brings on the shock. 

24. The beats of a healthy heart are regular 
and steady, like the working of a steam-engine. 
When the heart is out of order, its beating is 
irregular and unsteady. One of the causes of such 
a condition is tobacco. 

When a doctor says that Mr. A or Mr. B has a 



48 PHYSIOLOGY PRIMER. 

" smoker's heart/' he means that he has got his 
heart into this unsteady state by smoking or chew- 
ing tobacco. 



QUESTIONS. 

Sect. I. — 1. How is the blood held in the tissues? 

2. What are the three kinds of blood-vessels? 

3. What is the aorta? 

4. What are the capillaries? 

5. W^hat are the veins? Where can we see the veins? 

6. Where is the heart situated? Wliat is its shape? What is 
it made of? How is it divided? 

7. Describe a journey through the blood-vessels, starting in 
the heart. 

8. What two things might you notice on such a journey? 
What are the gates you pass? What are they like ? What is the 
name of the gate between the right auricle and ventricle? What 
is the name of the gates at the beginning of the aorta and of the 
pulmonary artery? What is the name of the gate between the left 
auricle and ventricle? 

9. How do we know that the blood is always moving in the 
blood-vessels? In which direction does it flow? 

10. What machine does the heart resemble? 

11. What can you hear and feel if you lay your ear against any 
one's breast? Does the heart get any rest? How much? 

12. How fast does the heart beat? What makes it beat faster ? 
Do we feel our hearts when we are well? 

13. What makes the heart beat? Describe the process. 

14. How can you illustrate a heart-beat? What is the size of 
the heart ? 

What does the heart do when it beats ? 

15. 16. Give another illustration of the action of the heart. 
17. How can you illustrate the circulation of the blood? 



QUESTIONS. 49 



18. What is the pulse? What causes the beating which you 
can sometimes see in the neck? 

19. What can be learned by feeling the pulse? , 

20. How does the blood come when an artery is cut? when 
capillaries are cut? when a vein is cut? 

21. What is the effect of alcohol on the heart? Is it wise to 
whip up a healthy heart? 

22. What changes can alcohol make in the substance of the 
heart? what changes in the blood-vessels? 

23. What disease threatens a man with brittle arteries? What 
is apoplexy? Do young persons often have it? What may cause 
it in a young person ? 

24. What is meant by the name " smoker's heart "? 



50 PHYSIOLOGY PRIMER. 



CHAPTER V. 



THE BLOOD.-WEAR AND REPAIR — 
THE LYMPHATICS. 

Sect. I. — 1. A man has in his body about six 
quarts of blood, — not quite an ordinary wooden 
pail full. It is the most precious of all fluids. 
For "the blood is the life," as says Scripture. 
That is the reason why some people turn sick 
and faint when they see blood flow. It is like 
seeing the life go out. A man can not lose more 
than half of his blood, and live. The loss of 
much less than half might be fatal. 

2. Blood is a red fluid so thick that you can not 
see through it. 

If you put a cut finger in your mouth, you find 
that blood tastes salty, and has a smooth feeling 
to the tongue. When fresh, it is warm. 

3. When any one is cut, the blood at first runs 
fast. In a little while, if the cut is not a very 
large one, it runs more slowly, and begins to grow 
thick ; and soon it stops altogether, even if you 
have not done much to stop it. If any of it has 
dropped on the floor, it will turn in a few minutes 
to a jelly-like mass. 



THE BLOOD. 51 



4. If you should go to the butcher's, and get a 
bowl full of fresh blood, and let it stand fifteen 
minutes, you would have a bowd full of this same 
jelly-like substance. This is called clotted blood. 

5. Fresh blood always clots when it flows out 
of the blood-vessels. It is well for us that it does 
so. If it did not clot, it w r ould keep on until you 
bled to death. It would not be safe to have a 
tooth pulled. As it is, the wound is soon plugged 
with clotted blood. 

6. But why does it not clot in the blood- 
vessels ? That we can not tell. We know that it 
does not, and we know that it does clot in the air. 
We know, too, that it clots more quickly when it 
is running slowly. 

If you press your finger on a cut, or tie a 
handkerchief over it, it will check the flow of 
the blood, and give it a chance to clot. Then, 
when you take your finger or your bandage off*, 
it will not start again. 

7. Sometimes the blood flows so fast that you 
can not stop it by pressing on the wound, or 
bandaging it. This happens when a large blood- 
vessel is cut. If it is an artery that is bleeding, 
you should tie a handkerchief or a cord tight 
around the limb, above the wound; below the 
wound, if it is a vein. 



52 PHYSIOLOGY PRIMER. 

8. How can you tell whether it is an artery or 
a vein that is bleeding ? 

(I.) Blood flows in spurts from an artery. It 
flows in a steady stream from a vein. 

(2.) Blood from an artery is bright scarlet in 
color. Blood from a vein is darker, nearly purple. 

If you can not tell by these indications, tie the 
handkerchief around the limb above the wound ; 
and, if that is not sufficient, tie one below also. 

These bandages can be kept on for an hour or 
two, if necessary, until a physician arrives. 

9. If you look at a drop of blood with a micro- 
scope, you will see a watery fluid 
with very many little round 
bodies floating in it. 

LqJI "^rtflJ^ ^ e wa ^ er y fluid is called the 

gxp xt plasma. The round bodies are 

called the corpuscles. Some of 

Fig. 12. * 

Red corpuscles of Human these corpuscles are white, but 

Blood (400 diameters). . n . -■ 7 

most oi them are red. 
The red corpuscles make rosy cheeks and cherry 
lips. Sometimes there are not so many of them 
as there should be, or they are pale in color. 
This makes pale faces and white lips. 

10. If we lay aside our microscope, and ex- 
amine blood by the aid of chemistry, we shall 
find that — 




WEAR AND REPAIR. 53 

(2.) Nearly four-fifths of the blood is water. 

(2.) The blood contains many substances, which 
come from the food we eat, and are for the nour- 
ishment of the body. 

(3.) The blood contains waste matters, which 
come from the wear of the body. 

(4.) The blood contains oxygen from the air. 

The blood, then, is the carrier of nourishment, 
waste, oxygen. 

WEAR AND REPAIR. 

11. Now we can begin to see what the blood 
is for, and why the blood-vessels carry it through 
every nook and corner of the body, and why the 
heart keeps pumping day and night. 

The body, like every thing else in the world, is 
all the time wearing out. Work and play, walk- 
ing, talking, breathing, even thinking, wear it. 

The little worn-out particles are of no further 
use. They must be cleared away. So they are 
drawn into the capillaries, and washed along into 
the veins, and, finally, they are cast out in one of 
three ways. 

c the lungs. 

Waste matter goes out by < the skin. 

I the kidneys. 

12. The body must be repaired as fast as it 
wears, or else it would soon be worn out. So 



54 PHYSIOLOGY PRIMER. 

the blood must take up the nourishment that is 
digested, and carry it around to all the little 
hungry particles of flesh and bone and nerve, to 
make up to them for what it takes away. 

13. Every little particle of the body wants 
oxygen. It can not live without it. The blood 
takes it in from the lungs, and carries it about 
for distribution. The red corpuscles are the boats 
in which the oxygen rides. It gets on in the 
lungs, and gets off in the different parts. 

14. So the blood is constantly changing. It 
takes up something here, and gives out something 
there. It may be compared to a train of freight- 
cars, which goes through the country loading and 
unloading at every station. As the people at each 
station take out what they need, and send away 
what they do not want, so each particle in the 
body takes out from the blood what it needs, and 
gives up what it does not want. 

15. You have learned that there are no open- 
ings out of the blood-vessels. How, then, can the 
nourishment from the blood get to the flesh, and 
how can the waste matters from the flesh get into 
the blood ? 

You remember that the arteries, as they divide 
and grow smaller, have thinner and thinner walls. 
The capillaries have the thinnest walls of all. 



THE LYMPHATICS. 



55 



They are so thin and delicate, that nourishment 
dissolved in the blood can 
soak out of them, and dis- 
solved waste matters can soak 
into them. Oxygen, too, can 
easily pass through. The cap- 
illaries are so near together, 
that almost every particle in 
the body is bathed in the fluid 
that soaks through them. 

THE LYMPHATICS. 

16. A cistern or tank for 
water generally has an over- 
flow pipe. There is a pipe to 
bring in the water, and a pump 
to draw it out, and, besides, a 
pipe near the top, through 
which the water can run off 
if it gets too full. The body 
has a set of overflow pipes. 
They are called lymphatics. 
These tubes do not begin at 
the heart, as the blood-vessels 
do. They begin among the 
capillaries all through the 
body. They are at first more delicate even than 




Fig. 13. 

Superficial Lymphatics of the 
Arm. 



56 PHYSIOLOGY PRIMEB. 

the capillaries. They join together, and grow 
larger, just as the veins do, and run toward 
the heart. They do not empty into the heart, 
but into the great veins near the heart. So all 
the fluid that they take up gets finally into the 
blood. 

17. All along the course of the lymphatics are 
little knots as large as a pea or a bean. These are 
called the lymphatic glands. In the neck they 
often swell, and are then sometimes painful. 

FAINTING. 

18. No part of the body can live long if its 
supply of blood is cut off. If a string were tied 
around your finger tightly enough to stop the 
flow of blood, and kept on, it would die. If the 
heart for any cause suddenly weakens, the head 
swims, the sense of sight and other senses fail, the 
consciousness is lost. This is a fainting-fit It 
means that the brain is not getting its usual sup- 
ply of blood. This weakening of the heart may 
be caused by fright, or bad air, or pain. Any one 
who is faint ought to be laid down fiat, because in 
that position the blood can flow to the brain more 
easily; and he ought to have fresh air, because 
that makes the blood better, and stimulates the 
heart. 



EFFECTS OF ALCOHOL AND TOBACCO. 57 

PURE BLOOD. 

19. Since the blood has so much to do with 
the life of the body, it is very important to keep 
it pure. 

We may keep the blood pure, — 

(I.) By exercise. The blood flows faster when 
we exercise, and keeps purer, just as a running 
stream is purer than a stagnant pool. 

(2.) By bathing. This keeps the skin active, 
and an active skin carries off impurities from 
the blood. 

(3.) By moderation in eating. When we eat too 
much, the blood is loaded with more nourishment 
than it can dispose of. 

(4.) By avoiding unwholesome foods. Somethings 
are unwholesome, even if you take but little of 
them. Unripe fruit or decayed fruit is so. 

Some things are wholesome if you take but 
little, but very unwholesome if you eat a great 
deal. Candy and rich cake, and sweetmeats or 
pickles, are of this class. 

EFFECTS OF ALCOHOL AND TOBACCO. 

SO. Alcohol is taken into the blood, and 
mingles with the other substances dissolved in 
it. It is not just like any of them. It does not 
belong anywhere. It is carried swiftly around 



58 PHYSIOLOGY PRIMER. 

in the current ; and, wherever it goes, it stirs up 
commotion. It whips the heart, and excites the 
nerves. It goes to every station on the road ; and, 
if there is more than a small quantity of it, they 
all refuse to take it in : and, finally, it is thrown 
out as useless by way of the lungs or skin or 
kidneys. 

Alcohol is an impurity in the blood itself, and 
it causes other impurities by injuring the stomach. 

A moderate use of alcohol often makes people 
crave too much rich and stimulating food. A 
great deal of alcohol takes away the appetite 
altogether. 

21. The nicotine which is contained in tobacco 
is taken into the blood through the lungs, the 
mouth, and stomach. By the blood, it is carried 
to every part of the body. Its effects do not 
appear immediately. Often it seems as if it were 
having no effect. In other cases, we can clearly 
see that it is poisoning the whole system. 



QUESTIONS. 

Sect. I. — 1. How much blood has a man in his body? How 
much can he lose, and yet live? Why do we feel faint at the sight 
of blood? 

2. What is the color, taste, and feeling of blood ? 

3. What happens when we are wounded? 



QUESTIONS. 59 



4. What is clotted blood? 

5. What good purpose does clotting serve? 

6. Does blood clot in the blood-vessels? How can you help it 
to clot in a wound? 

7. What can you do when you can not stop the blood by 
bandaging the wound? 

8. How can you tell whether blood comes from an artery or 
a vein? 

9. How does a drop of blood look under a microscope ? What 
is the watery part called? What are the round bodies called? 
What is the color of the round bodies? Wliat makes rosy cheeks? 

10. What is the chief part of the blood? 

What three things does the blood contain? Where does each 
one of these things come from? 

11. Does the body wear? What becomes of the worn-out 
particles ? 

By what three ways does waste matter go out of the body? 

12. How is the body repaired? 

13. How is the oxygen carried in the blood? 

14. Is the blood always the same ? 
How is it like a freight-train? 

15. How does nourishment get out of the blood, and waste 
matter get in? 

16. What are the lymphatics ? What do they do? 

17. What are the lymphatic glands ? 

18. What is constantly needful for the life of the body? What 
is a fainting-fit? What should be done with a person who has 
fainted? Why? 

19. Why is it important to keep the blood pure? How may 
we keep it pure ? 

Is unripe fruit ever wholesome? 

Are candy and cake ever wholesome? 

20. What does alcohol do in the blood? What becomes of it 
at last? 

How does alcohol affect the appetite ? 

21. How does nicotine enter the blood? What is its effect? 



60 PHYSIOLOGY PRIMER. 



CHAPTER VI. 



FOOD AND WATER. — STIMULANTS AND 
NARCOTICS. 

Sect. I. — 1. The blood carries nourishment to 
every particle of the body. Let us inquire now 
what this nourishment is, and where it comes 
from. It is contained in food and water. And 
all our food and water come from the earth and 
the air. Think of this, and see if you can remem- 
ber any kind of food that does not come from the 
earth or air, 

2. Perhaps you will say, beef does not. But it 
does. For the ox lives on grass and grain, and 
grass and grain come from the earth and air. So 
with all kinds of meat. The food of all animals 
comes at last from plants. 

3. The food of plants is the air and the min- 
erals which are dissolved in the earth. 

Animals can not live on air and minerals. 
Plants can. That is one great difference between 
animals and plants. And one great business of 
the plants is to take air and minerals into them- 
selves, and make them into food for animals. 



ANIMAL FOOD. 61 



Probably every plant is food for some kind of 
animal, big or little. 

4. If you were lost in a forest, you would very 
likely starve to death. All around you the birds 
would be full of life, and the rabbits and squirrels 
and foxes would be growing fat. But, unless you 
could manage to catch some of these animals, you 
would have nothing to eat. What is food for a 
bird or a squirrel or a horse, is not food for you. 

But there are some plants that you can eat. It 
is the business of farmers to raise these plants. 
Farmers also take care of the animals that are 
food for men. 

ANIMAL FOOD. 

5. The most nourishing animal food is beef. 
Lamb and mutton and fowls come next. Many 
people eat pork more than any other meat. It is 
not so digestible or healthful as beef and mutton. 
It ought always to be well cooked. 

Raw ham and raw sausages are dangerous. 
They often contain a little worm, called the tri- 
china, which causes a severe disease in those who 
eat them. The trichina is killed by thorough 
cooking. 

6. Fish is a light and digestible food. But it is 
much better on the seacoast, or near the places 
where it is caught, than elsewhere. It spoils by 



62 PHYSIOLOGY PRJMER. 

being kept, sooner than beef or mutton, and is 
likely to lose its fine flavor when it is carried far. 

7. Oysters are a favorite food with very many. 
They are easily digested and nutritious. It is a 
good rule to eat them only in the months that 
have an r in them. 

8. Eggs contain a great deal of nourishment, 
and are easily eaten. 

9. There is no one food as valuable as milk. 
Infants live on it for the first year or two, and 
sick people can live a long time on it when they 
can not take any thing else. 

VEGETABLE FOOD. 

10. The principal grains used as food are wheat, 
rice, corn, oats, rye, and barley. 

Many millions of the human family live on 
rice. It is the chief food in China, India, and 
some other countries. 

In Europe and America, wheat is the most val- 
ued grain. Corn contains the most oil, and is a 
richer food than the others. Oatmeal contains 
much bran, and is a coarse article of diet; but 
it is wholesome for most people. 

11. No vegetable is used more generally in civ- 
ilized countries than the potato. It is a native of 
North America, and was introduced into Europe 



COOKING. 63 



three hundred years ago. Since that time it has 
become the chief food of great numbers of people. 
No other vegetable is so light and delicate. 

12. Dried pease and beans are hard to digest, be- 
cause they contain so much solid matter. But, for 
this very reason, they are good for armies, or for 
men who are exploring or hunting, who have to 
carry a good deal of nourishment in small bulk. 

13. Green garden vegetables are healthful, on 
account of the juices which they contain. 

COOKING. 

14. Animals eat their food raw. Men cook 
most of theirs. Cooking makes food more digest- 
ible, and it gives good flavors. It makes a great 
difference with our appetites whether our food is 
well cooked, or not. There is no art which has 
more to do with health and comfort than cookery. 
It is therefore worth learning. 

15. Bread is so large a part of our diet, that it 
is worthy of more attention than any other article. 
Good bread is light and sweet. In order to have it 
light and sweet, you must have, — 

(1.) Good flour. 
(2.) Good yeast. 
(3.) Good mixing. 
(4.) Good judgment 



64 PHYSIOLOGY PRIMER. 

The good judgment must be gained by experi- 
ence, and is used in deciding when the mass is 
warm enough, when it has risen long enough, 
when the oven is hot enough, and when the bread 
should be taken out. 

Sour bread makes sour tempers. 

Hot bread is not so light and digestible generally 
as cold bread. 

16. Besides bread, pastry and cake are made of 
grain. These contain lard or butter, and sugar. 
This makes them rich, and pleasant to the taste. 
A moderate quantity of them does no harm ; but, 
if we eat heartily of such food, we are giving the 
stomach too much work to do. 

MINERAL FOOD. 

17. The only mineral that we eat by itself is 
salt. It is a great hardship to be deprived of it. 
It helps digestion, and is very necessary in the 
body. Some animals need it as much as men. 
The cattle on the Western plains Avill go a long 
distance to find a salt-spring. 

But it is poison to fowls. 

Other mineral substances are contained in many 
articles of food. 

WATER. 

18. When we remember that about eight-tenths 



WATER. 65 



of the blood is water, and that about seven-tenths of 
the whole body is water, and that we are losing 
water constantly through the lungs and the skin 
and the kidneys, we can see why it is so necessary 
to us. We can bear to go without food better than 
to be deprived of water. 

19. Good drinking-water is clear and transpar- 
ent, and it has no taste or odor. But even water 
with no taste or odor is sometimes bad. There are 
many poisonous substances which may be dissolved 
in w r ater, which will not give it any smell or taste 
or color. People often drink bad water without 
knowing that it is bad. 

It is important to be careful of the drinking- 
water, to see to it that nothing harmful gets 
into it. 

20. Water that runs through lead pipes may 
have a little lead dissolved in it. You can not 
taste it or smell it or see it. It does not make you 
sick at once. But by and by you find that a dis- 
ease is upon you. Even if you stop drinking the 
water, it may be a long time before you are well. 

Intoxicating drinks sometimes act just like 
water with lead in it. They do not seem to do 
any harm at first. The drinker is well, and they 
make him feel better. But by and by he knows 
that they are injuring him. Then, when he tries 



66 PHYSIOLOGY PBIMJEM. 

to stop, he finds that he has got a habit of taking 
them which he can not easily break. 

It is not safe to use lead pipes unless we know 
that the water we use does not act on them. It 
may be necessary to ask the opinion of a chemist. 

21. Water may have foul matters in it from 
sewers and drains. This sometimes happens to 
the drinking-water of cities. You would suppose, 
that, in the country, the water would always be 
pure. But, in many a farmhouse, they are drink- 
ing water that has in it slops from the sink, or 
drainings from the barnyard. So they get typhoid 
fevers, and other diseases. 

22. The well should never be within thirty feet 
of a pigpen or barnyard, or other foul spot. It 
should never be where the ground slopes down to 
it from any such place. 

When it is necessary to use water that is not 
pure, it should be boiled and filtered. This makes 
it safer. 

HABITS. 

23. People of different countries prefer different 
foods. In Ireland, the potato holds the first place; 
in Scotland, oatmeal ; in India and China, rice. 
In hot climates, a very little food is sufficient. An 
Arab can travel all day with no other food than a 
handful of grain ; but an Esquimau, after fasting, 



STIMULANTS AND NARCOTICS. 67 

will eat several pounds of clear fat at a meal. In 
some countries, almost nothing is eaten before 
noon. In cold northern latitudes, people want a 
hearty breakfast. 

24. So people in the same country differ in 
their habits. One prefers one kind of food, and 
another another kind. One dines at noon, another 
at night. It is not necessary that all should have 
the same habits, but there are some rules which 
all should observe. 

We should remember that we eat to live, and do 
not live to eat 

We should eat nothing that we know to be harmful 
to us, even if it be very pleasant to the taste. 

We should not eat too much. 

STIMULANTS AND NARCOTICS. 

Sect. II. — 1. Did you ever get too much pepper 
in your mouth ? Did it make your tongue smart, 
and set you to coughing, and make your eyes 
water? If so, you know what a stimulant is. To 
stimulate means to excite, to stir up, to irritate. 
A stimulant is any thing that excites and stirs up 
and irritates. The pepper irritated your tongue 
and throat, and stirred you up. 

2. Mustard is another stimulant Horse-radish, 
spices of all kinds, and many herbs, are stimulants. 



68 PHYSIOLOGY PRIMER. 

We want only a little of them with our food, — so 
little, that they are not worth any thing for the 
nourishment they contain. But they give food a 
flavor, and arouse the appetite. 

In this way pepper and mustard may not be 
harmful if used moderately. 

3. But, after all, "Hunger is the best sauce." 
What we really want, when we sit down to eat, is 
the nourishment that is in the plain food, and not 
the pleasure that the taste of spices gives us. One 
whose health is good does not often need to have 
his appetite stimulated. By spiced and highly 
seasoned food, we are easily tempted to eat too 
much. 

4. Such food is not as well digested. The good 
stomach, which is faithfully doing its work, does 
not like to be stirred up by too much spice, any 
more than your tongue likes too much pepper ; so 
it feels badly, and can not act as well. 

5. By indulgence in any kind of stimulants, the 
desire for them is likely to increase. We may learn 
to bear larger and larger quantities, until all food 
that is not very highly flavored seems flat to us. 

TEA AND COFFEE. 

6. Tea and coffee are stimulating drinks. Tea is 
made from the leaf of a plant which is cultivated 



opium. 69 



in China and Japan, and coffee from a berry which 
is brought from Arabia, and other warm countries. 
Like the food-stimulants just spoken of, they do 
not afford much nourishment. They are used for 
the warmth and comfort which they give. 

7. Probably you are not allowed to have any. 
This is right. Grown persons are not injured by 
them so much as children, whose bodies are more 
delicate, would be. But grown people are some- 
times injured very much by them. They hurt 
their stomachs, and give them headaches, and 
make them nervous and fretful and unhappy. 
Some people ought never to use tea and coffee. 
Every one ought to be careful, and not take too 
much. 

OPIUM. 

8. When a person is sick and in pain, the 
doctor sometimes gives him a dose of opium. In 
a little while, the pain grows less and less, and 
then goes away entirely. Instead of groaning 
and crying, he can smile. Then he finds that he 
is drowsy. His eyelids droop. He forgets his 
trouble, and soon he is quietly sleeping. It is 
the opium that has done this. 

9. There are many other drugs, which, like 
opium, can make a person quiet or drowsy or un- 
conscious. We call them narcotics. Some things 



70 PHYSIOLOGY PRIMEB. 

are both stimulants and narcotics. If a man takes 
a single glass of wine, it is a stimulant. It excites 
him. If he takes a great many, and becomes 
drunk and stupid, it is a narcotic. 

10. Opium is a blessing when properly used by 
the physician. But, when improperly used, it is 
a terrible evil. Those who take it a good while 
come to depend on it. It is even harder to give it 
up than to give up drinking. People use it, not 
to relieve pain only, but because it gives pleasure. 
They may not know, when they begin, that it can 
harm them. At first they only feel the pleasant 
effects. But by and by they find that it is making 
them sick and weak in body and mind. They 
become good for nothing. Since there is this 
danger in it, it ought never to be taken except 
when the doctor orders it. 

11. Opium is the juice of the poppy. This 
plant grows in our gardens, and has a beautiful 
flower; but most of the opium is brought from 
the East, where fields of poppies are cultivated. 
Laudanum is opium in a liquid form. Morphine is 
a white powder Avhich is made from opium. It 
has the same effects, but it does not take so much 
of it to produce them. 



TOBACCO. 



TOBACCO. 

12. Tobacco is the leaf of a plant which was 
found in this country when it was discovered by 
Europeans. The Indians taught the new-comers 
the use of it. After being thoroughly dried, it is 
smoked and chewed and snuffed. A great many 
men use it, and some boys. They do it because 
they like its effects. They say it makes them feel 
better, and helps them to do their work. 

13. Some men who use tobacco do not seem to 
be injured by it. They are healthy and strong, 
and live to be old. Others are injured very much. 
Sometimes they do not know that it is hurting 
them. Sometimes they know it, but can not give 
it up. 

The first time it is used, it makes the user 
deathly sick. Nature rebels against it. After a 
time, it does not cause sickness, but gives pleasure. 

14. But, while it is giving pleasure, it may be 
doing harm in several ways, — 

(i.) By weakening the stomach. 

(2.) By making the throat sore. Smokers often 
have sore throat. Cancer in the throat or mouth 
is at times occasioned by smoking. 

(3.) By disturbing the heart. It makes it irreg- 
ular and weak. 



PHYSIOLOGY PRIMER. 



(4.) By making the nerves unsteady. 

15. Tobacco is especially bad for boys. It may 
stop the body and mind from growing, and make 
them feeble and unhealthy in every part. 

ALCOHOLIC DRINKS. 

16. Wines are made of the juice of grapes or 
berries. Beer, ale, porter, and whisky are made from 
grain. Brandy is made from wine and cider and 
some other liquors. Rum is made from sugar-cane 
or molasses. All these drinks contain alcohol, 
and it is for the alcohol in them that they are 
used. 

17. Alcohol looks like water. It burns the 
mouth like fire if it is taken clear. Brandy is 
about half alcohol. Wine is from one-tenth to 
one-fifth alcohol. 

18. Many men spend more money to get alco- 
holic drinks than they spend for food or clothes 
or any thing else. Why do they want them so 
much? 

You have already learned, that, when you take 
any stimulant for a while, you are likely to get 
fond of it, and to want more and more of it. This 
is especially so with alcoholic drinks. The appe- 
tite for them often keeps growing, until it is 
stronger than any other desire. A moderate 



QUESTIONS. 73 



drinker is always in some danger of becoming a 
drunkard, and a drunkard will give up every 
thing for liquor. 

19. All stimulants are sometimes an injury to 
those who use them. But no other one has such 
power as alcohol. It can change a man into some- 
thing worse than a beast. It can take away his 
property and his home. It can destroy his char- 
acter. 

It makes more people poor and unhappy and 
wicked than any other cause. 



QUESTIONS. 

Sect. I. — 1. What is our nourishment contained in? Where 
does it all come from? 

2. From what does the food of all animals come? 

3. What is the food of plants? What great difference is there 
between plants and animals? What service do plants render to 
animals ? 

4. Can all animals live on the same food? From whom do we 
get our food? 

5. What is the most nourishing animal food? What comes 
next? What caution should be observed in eating pork? 

6. What caution should be observed in buying fish? 

7. In what months are oysters best? 

9. Which is the most valuable food? 

10. Name the principal grains used as food. 
What is the chief food in China and India ? 

What grain is most valued in Europe and America ? 

11. What vegetable stands first, in usefulness? 



74 PHYSIOLOGY PRIMER. 

12. For what purpose are dried pease and beans very valuable? 

14. Is good cooking important? 

15. What is necessary for making good bread? 

16. What is the difference between bread and cake and pastry? 
Are cake and pastry wholesome? 

17. W^hat mineral do we eat with our food? Do we eat any 
other minerals in our food ? 

18. How much of the blood is water? How much of the body 
is water? Why must we keep drinking it? 

19. Describe good drinking-water. Is all water good that 
looks and seems good? 

20. What mineral sometimes gets into water? How are intoxi- 
cating drinks like poisoned water? 

What should we be sure of if we drink water that comes 
through lead pipes? How can we be sure of it? 

21. What injurious substances that are not minerals get into 
water? What is a result of drinking such water? 

22. What is the rule about the position of the well? How can 
we make bad water safer? 

23. Do all countries have the same habits of eating? 

24. Do people in the same country have the same habits of 
eating? Is it important that they should? 

What rules ought all to remember? 

Sect. II. — 1. What is a stimulant ? 

2. What is the use of stimulants? 

3. What is the chief object of eating? Do stimulants contain 
much nourishment? 

4. What is the harm of food stimulants? 

5. What is the danger of indulgence in them ? 

6. What is tea? What is coffee? What are they used for? 

7. Are tea and coffee good for children? Are they always good 
for grown people ? 

8. What is the effect of opium? 

9. What is a narcotic? 



QUESTIONS. 75 



10. How does opium do harm ? Is it safe to use it? 

11. What is opium? laudanum? morphine? 

12. What is tobacco? Why do men use it? 

13. What are its effects? 

14. How may it do harm ? 

15. Who are most injured by tobacco? 

16. Name some alcoholic drinks, and state what they are 
made of. 

17. What does alcohol look like? How much alcohol is there 
in brandy ? How much in wine ? 

18. Why do men spend so much money for alcoholic drinks? 

19. What does alcohol do? 



PHYSIOLOGY PRIMER. 



CHAPTER VII. 



DIGESTION. —ABSORPTION. 

Sect. I. — 1. Let us suppose ourselves to be 
examining the body of a dead animal. We have 
studied the skin, and have removed it. We have 
studied the muscles (or flesh) which lie beneath. 
With the aid of a microscope we have studied 
the blood which flows as we cut the flesh. We 
will next cut through into the inside, and see 
what we find there. 

2. We find, first, that the inside of the trunk 
is divided into two parts by a thin partition, that 
extends across from the breast-bone to the back- 
bone. This partition is called the diaphragm. It 
is made of muscle, and can move up and down. 
The part above the diaphragm is called the thorax, 
or chest. The part below is called the abdomen, 
or belly. 

3. The things that we notice in the chest are, 
two lungs, a heart, and a soft fleshy tube which 
runs through it from top to bottom. This tube 
is the oesophagus, or gullet. 

4. In the abdomen we see the liver, the pan- 



DIGESTION. 77 



creas, the spleen, the kidneys, the stomach, and 
the intestines, or boicels. 

5. If we follow the soft tube — the gullet — that 
we noticed in the chest, upwards, we find that it 
opens into the throat, and the throat opens into 
the mouth. If we follow it downwards, we find 
that it goes through a hole in the diaphragm, and 
then it opens into one end of the stomach. If 
we follow on to the other end of the stomach, we 
find that the stomach opens into the bowels. The 
bowels are coiled up in the abdomen, and end at 
the lower end of the trunk. 

6. This long tube, which begins at the lips, 
and extends through the trunk, is called the 
alimentary canal. Aliment is nourishment. The 
alimentary canal is the canal in which nourish- 
ment is made fit to be taken into the blood. 

H. The alimentary canal is to the body what the 
kitchen is to the house. Food, as it comes from 
the butcher and the grocer, is first carried to the 
kitchen. There it is cut up and ground and 
cooked ; and finally it comes to us in nice, 
tempting dishes, to satisfy the hunger of the 
family. 

So, in the alimentary canal, the food we eat is 
cut up, and the nourishing part is separated from 
that which is not nourishing, and is softened to a 



78 



PHYSIOLOGY PRIMER. 



liquid, and changed so that it can be taken into 
the blood, and carried to all parts of the body. 
We call this digestion. 

8. This canal is very important, and we must 
study it further. 

The alimentary canal is from twenty-five to 




Fig. 14. 
1. The Heart. 2. The Lungs. 3. The Diaphragm. 4. The Liver. 5. The Gall -Blad- 
der. 6. The Stomach. 7. The Bowels. 

thirty feet long in a man. Of course, in order 
to get such a long tube into the trunk, which is 
only about two feet long, part of it must be rolled 



DIGESTION. 



79 



up in a coil. The coil is the part of the tube that 
we call the boivels. 

9. The lips are the gates which close the en- 
trance to the canal. Behind these gates is the first 
cavity, the mouth. Liquid food does not stay in 
the mouth, but passes directly through it. Solid 
food must be chewed before it can go on. 

10. A baby when he is born has no teeth. But 
by the time he is six or seven months old they 
begin to come. The lower front teeth are the first 
to peep out. At two years of age he will have 
twenty teeth. This is his 
first set, called milk teeth 
or baby teeth. At about 
five years of age he be- 
gins to lose these, and 
new ones take their 
places. The new ones 
keep coming; and the 
last, which are called 
wisdom teeth, may not ap- 
pear before twenty-five or thirty years of age. A 
grown person has thirty-two teeth, — twelve more 
than a child. 

11. The front teeth are flat and sharp, like 
chisels. They are for cutting. Two on each 
side — the eye-tooth and the stomach-tooth — are 




Fig. 15. 

The Lower Teeth. 




80 PHYSIOLOGY PRIMER. 

pointed for holding on to things. The back 
teeth have broad ends for grinding. 

12. Each tooth has one or more roots, which fit 
in a socket in the jaw-bone. 
Enamel Bfi^i The surface of the tooth is 

enamel, which is the hardest 
central »!»» substance iii the body. In the 

center of the tooth is a canal 
which contains little blood- 
vessels and nerves. 

13. Teeth are liable to de- 
Fi S . is. ca y When they do so, they 

Back Tooth sawed in two. * ■/..«/ 

are sensitive and painful; and 
finally they crumble away entirely. If we lose 
one of our first teeth, it is not much of a loss; 
for a new one will soon grow. If we lose a second 
tooth, the dentist must make us another, or we 
must go without. 

14. People do not look as well when their 
teeth are gone; and, besides, they can not chew 
their food as well. 

It is important, therefore, to take good care of 
the teeth. 

We must not bite nuts or other hard things 
with them. If they are broken or chipped, they 
can not be restored. 

We must keep them clean. They should be 



DIGESTION. 81 



well brushed every day. Food left between the 
teeth injures them. 

If they begin to decay, they should be taken 
care of immediately by a dentist. He can often 
save them. 

15. When you bite any thing, your lower jaw 
moves down and up. When you chew any thing, 
it moves from side to side, as well as down and 
up, so that the food is ground between your back 
teeth. 

16. The tongue is made of muscle. Some of 
the fibers run lengthwise, some crosswise, some 
up and down. It can lengthen and thicken, and 
move in every possible direction. 

17. Now, suppose you have bitten off a piece 
of bread. Immediately your jaw moves down 
and up and sidewise. Your tongue and cheeks 
keep the morsel all the time between your teeth, 
sometimes shifting it from one side of the mouth 
to the other ; and so it is cut and ground into fine 
bits. 

18. While you are chewing, your mouth is 
moist. As soon as you begin, — sometimes before 
you begin, when you are thinking of nice food, 
— your mouth waters. This water is the saliva. 
It comes from six lumps, which are called the 
salivary glands. Two of them are just under 



82 



PHYSIOLOGY PRIMER. 



the ears. When we have mumps, these swell up, 
and are sore. Four of them are under the floor 



of the mouth. 



These glands make the saliva 




Fig. 17. 

Salivary Glands. 



out of the blood, in the same way that the sweat- 
glands make sweat from the blood. A little tube 
runs from each of them, which opens into the 
mouth. The saliva pours through these tubes. 

19. Your mouthful of bread, while it is being 
cut up and ground, is being moistened with saliva. 
When you are ready to swallow it, it is a soft 
pulp. 

If you are in a hurry, you may manage to 
swallow food that is not thoroughly chewed, and 
mixed with saliva. This gives the stomach more 



DIGESTION. 83 



work to do. Sometimes it makes it ache. So we 
should be sure and take time enough. 

20. When we swallow, the tongue forces the 
morsel of food into the throat, and the muscles 
of the throat close around it, and squeeze it 
down into the gullet. Then the walls of the 
gullet, which are muscle, contract behind it, and 
squeeze it down into the stomach. If you look 
at a horse when he is drinking, you can see the 
swallows of water passing one after another along 
his neck. 

21. The stomach is a part of the alimentary 
canal which is larger than the rest. It is a pouch 
in which the food stays some time, and is changed 
a good deal. In a man it is about twelve inches 
long, and three or four inches wide. It lies just 
under the heart. When it is full, it presses up 
against the heart and lungs ; and that is the reason 
why we are short of breath if we run just after 
dinner. 

22. The wall of the stomach is partly muscle. 
It has a pink lining, like the lining of the mouth. 
This lining is full of little pits shaped like the 
finger of a glove. They are the stomach-glands. 
They make the gastric juice from the blood, and 
the gastric juice digests a part of the food. 

23. As soon as the morsel which is swallowed 



84 



PHYSIOLOGY PRIMER. 



drops into the stomach, the blood comes to its 
lining, and makes it redden, just as your face 
reddens when you blush. Then the stomach- 
glands make gastric juice quickly. At the same 



(Esophagus. 



Pylorus 



Stomach. 



Bowel 




Fig. 18, 

Section of the Stomach. 



time, the walls of the stomach contract, and squeeze 
the food, as if you should put some pudding in a 
bag, and squeeze it with your hands. In this way, 
the gastric juice is well mixed with it. You do 
not know by your feelings that your stomach is 
contracting in this way. The muscle in it is in- 
voluntary muscle, and it contracts of itself. 

When the food has been kneaded in this way 
long enough, it slips out of the stomach into the 
bowels. 



DIGESTION. 85 



24. At the beginning of the bowels, at the right 
end of the stomach, there is a ring of muscle 
around the tube, which is called the pylorus. 
Pylorus means " keeper of the gate." Until the 
food has been thoroughly acted on by the stomach, 
this keeper shuts the gate, and will not let it out. 

25. When you eat too much, or take unwhole- 
some food, such as unripe fruit, the stomach tries 
to digest it, and finds it can not. Then it wants 
to get rid of it. The pylorus will not let the food 
out in that way; so the stomach makes a great 
effort, with the help of some other muscles, and 
throws it out by the same way through which it 
came in. Then the stomach feels better. 

26. In 1822 a Canadian, named St. Martin, was 
shot in the left side in such a way, that, when 
he got well, there was a hole into his stomach. 
Through this hole, the inside of the stomach could 
be seen, and things could be put in, and taken out. 
In this way, much of what we know about the 
action of the stomach was learned. 

27. When the stomach is through with the 
food, the pylorus opens the gateway, and lets it 
into the bowels. Near the beginning of the bowels, 
a small opening can be found. Two tubes are con- 
nected with this opening. One comes from the 
liver, the other from the pancreas. 



86 



PHYSIOLOGY PRIMER. 



28. The liver is a solid mass weighing four 
pounds. It is under the edge of the ribs, most of 
it on the right side. It makes yellow bile from the 
blood which runs through it. This bile is poured 



Liver. 



Gullet. Pancreas. 



Gall Bladder- 



Bowels 




Spleen. 



Bowels. 

Fig. 19. 

The Liver and other Organs of Digestion. 

out, through the tube just spoken of, into the 
upper end of the bowels. There it mixes with 
the food, and helps digestion. The liver also 
makes, and stores up in itself, a substance called 



DIGESTION. 87 



glycogen. Glycogen is changed into sugar for the 
use of the body as it is wanted. 

29. The gall-bladder is a little sac shaped like a 
pear, which is attached to the under side of the 
liver. Some of the bile made by the liver is 
stored up in the gall-bladder when it is not needed 
in the bowels. 

30. The tube from the liver sometimes gets 
clogged. That dams up the bile; and the bile 
gets into the blood, and is carried all through the 
body. It gives a yellow color to the skin and 
the eyes. This disease is called jaundice. 

31. The tube from the pancreas ends at the same 
opening with the tube from the liver. The pan- 
creas is the sweetbread in calves. It is six or seven 
inches long, and lies across the backbone behind 
the stomach. The fluid that it makes is called the 
pancreatic juice. This mixes w r ith the food in the 
bowels, and helps to digest it. 

32. The lining of the bowels is filled with little 
pits similar to those in the stomach. They make 
the intestinal juice. 

Divisions of the Alimentary Canal. 

The mouth. The oesophagus. 

The throat. The stomach. 

The bowels. 



88 PHYSIOLOGY PRIMER. 

Fluids of the Alimentary Canal. 

The saliva. The bile. 

The gastric juice. The pancreatic juice. 

The intestinal juice. 

ABSORPTION. 

Sect. II. — 1. Perhaps you are ready to ask 
how the nutriment gets into the blood after it is 
prepared by digestion, since there is no opening 
out of the alimentary canal. 

If you should examine the lining of the ali- 
mentary canal very carefully, you would see that it 
is full of the little blood-vessels called capillaries. 
The walls of these vessels are thinner than the 
thinnest paper. The nutriment which has been 
dissolved by the juices in the alimentary canal 
soaks through into these vessels, and is carried by 
the current of the blood to all parts of the body. 
The soaking process is called absorption. 

2. Absorption goes on in all parts of the 
alimentary canal. As the nutriment is digested, 
it is absorbed. A good deal is taken out of the 
stomach. While the food moves down through 
the bowels, more and more of it is absorbed, 
until at last there is no nutriment left. Only 
those parts of the food remain which can not 
be digested. 



RULES FOR THE CARE OF TUE STOMACH. 89 

3. If we are well, and eat only wholesome food, 
we shall not have to think any thing about our 
digestion. It takes care of itself. But, if we are 
not reasonable about our eating, we may have a 
great deal of trouble. Dyspepsia means bad diges- 
tion. Since it is our food that gives us strength 
and comfort, we shall not be strong or happy if 
we can not digest well. Dyspeptics suffer a great 
deal, and we should take good care not to get 
dyspepsia. 

RULES FOR THE CARE OF THE STOMACH. 

Sect. III. — 1. We should not eat too fast. It 
takes time to chew our food properly. If we swal- 
low it down in lumps, the stomach will have hard 
labor to take care of it. 

2. We should not eat too much. If we feel heavy 
and full after a meal, it is a sign that we are not 
well, or that we have overloaded our stomachs. 
It is foolish to stuff down food which we do not 
need because it tastes well. 

3. We should not eat too often. The stomach 
needs rest as well as the other parts of the body. 
If we keep it at work continually, it will wear out. 

4. Pie and cake and candy should not be eaten 
freely, like bread or fruit. A little of such food is 
sufficient. 



90 PHYSIOLOGY PRIMER. 

5. When you find that any thing you eat hurts 
you, do not eat of it again. If you have eaten 
green apples or cucumbers, and have had a stom- 
ach-ache after it, let them alone in future. If you 
have eaten two pieces of pie, and feel sick, eat 
only one piece next time. If you feel badly after 
eating any thing, it is a sign that it is not good for 
you. That is the way Mother Nature teaches us. 

EFFECTS OF ALCOHOL AND TOBACCO. 

Sect. IV. — 1. Alcohol is a fiery stimulant You 
remember what a stimulant does in your mouth, 
— such an one as pepper, for instance. Alcohol 
you could not keep in your mouth a moment. 

2. The mouth and stomach are made for simple 
food. If we are well, they do not need any strong 
stimulants. Too much mustard or tea is bad for 
them. 

3. Alcohol is a much more dangerous stimulant 
than these. Nobody drinks clear alcohol. The 
strongest drinks are about one-half alcohol, and 
the weakest have only three or four spoonfuls to a 
tumblerful. 

4. But you have learned, that, when we like 
any stimulant, we are apt to want more and more 
of it, until we get so that we need a great deal to 
satisfy us. 



EFFECT OF ALCOHOL AND TOBACCO. 91 

No stimulant is so enticing as alcohol. It is very 
easy to get into the habit of using a great deal of it. 

5o Since the stomach was not made to need 
strong stimulants, it hurts it to use them. 

Dr. Beaumont found, that when St. Martin took 
wine, beer, or any of the intoxicating liquors 
freely for some days, the lining of his stomach 
looked red and inflamed and sore, and the gastric 
juice became thick and ropy. 

6. If a boy handles a bat a good deal, he may 
get his hands blistered at first. By and by the 
skin will grow thick and hard. In the same way, 
the ends of a girl's fingers may get hardened by 
sewing. So, if the stomach is irritated constantly 
by alcohol, it will grow thick and tough. 

7. An old toper can drink a great deal of strong 
liquor without feeling it. That is because his 
stomach has changed. It is a better stomach to 
hold alcohol, but not so good a stomach to digest 
food. 

8. Drinking often causes dyspepsia. It takes 
away the appetite, and spoils the gastric juice. 

After long use of alcohol, the stomach some- 
times gets into such a condition that it will not 
bear food at all, without being first roused by 
drink. 

9. Drinking often causes diseases of the liver. 



92 PHYSIOLOGY PRIMER, 

10. He who uses tobacco for the first time finds 
to his cost that it also has a powerful effect on 
the stomach. It has a tendency to take away the 
appetite for food, and, in many cases, is one of 
the causes of dyspepsia. 



QUESTIONS. 

Sect. I. — 1, 2. What is the name of the partition which, divides 
the inside of the trunk? What is the name of the part above the 
partition? of the part below the partition ? 

3. What do we notice in the chest ? 

4. What do we notice in the abdomen? 

5. If we follow the gullet up, what do we find? If we follow it 
down, where does it lead us? Where are the bowels situated? 

6. What is the name of the long tube we have just been tra- 
cing ? What is aliment ? 

7. What may the alimentary canal be compared to ? What is 
digestion? 

8. How long is the alimentary canal? How can so long a tube 
be contained in the trunk ? 

9. Where does the alimentary canal begin? What is the first 
cavity in it ? 

10. When do a baby's teeth begin to come? When does he 
have them all? How many has he? When does he begin to lose 
his first teeth? When does a grown person have all his teeth? 
How many has he? 

11. Are the teeth all alike? 

12. Describe a tooth. 

13. Do teeth decay? 

14. Why is it important to take care of the teeth? Mention 
three rules for taking care of the teeth. 



QUESTIONS. 93 



15. What are the motions of the lower jaw ? 

16. Describe the tongue. 

17. 18. What is done with food in the mouth? What is saliva? 
Where does it come from? What is swollen when you have 
mumps? How is saliva carried into the mouth? What do you 
mean when you say your mouth waters? 

19. What is the harm of eating too fast? 

20. Describe the process of swallowing. 

21. What is the stomach? its size? its position? Why are we 
short-breathed when we run after dinner? 

22. What is the wall of the stomach partly made of? What 
are the stomach-glands? What do they make? 

23. Describe what takes place in the stomach when food 
enters it. 

24. What is the pylorus? What does it do? 

25. How does the stomach sometimes relieve itself of indigest- 
ible food? 

26. How do we know what goes on in the stomach? 

27. Where does the food go when it leaves the stomach? 

28. What is the liver ? What two things does it do? 

29. What is the gall-bladder? 

30. What is jaundice? 

31. What is the pancreas? What is it for? 

32. What is the intestinal juice? 

Name the divisions of the alimentary canal. 
Name the fluids of the alimentary canal. 

Sect. II. — 1. How does nutriment get into the blood? 

2. Where does absorption go on? 

3. What is dyspepsia? 

Sect. III. — 1-5. Give five rules for the care of the stomach, 
with the reason for each. 

Sect. IV. — 1. What effect has alcohol in the mouth? 



94 PHYSIOLOGY PRIMER. 

2* Does the healthy mouth and stomach need strong stimu- 
lants? 

3. Is clear alcohol used as a drink? 

4. What is one of the chief dangers of alcohol ? 

5. What can alcohol do to the stomach? 

6. 7. How may alcohol change the stomach? 

8. What disease of the stomach does drinking often cause? 

9. How does drinking affect the liver? 

10. What effect may tobacco have on the stomach? 



RESPIBATION. 95 



CHAPTER VIII. 



RESPIRATION. —THE VOICE. 

Sect. I. — 1. You might live several days with- 
out food and water, but you could not live five 
minutes without air. If any thing covers your 
mouth or nose, so as to prevent your breathing, 
you are in distress until you get it away. If you 
should sink under water, you would die, because 
the water would shut out the air. 

3. All animals need air. Even 
fishes must have it. There is some 
air dissolved in water. If you put a 
fish in a glass jar full of water, and 
then, with an air-pump, draw the air 
out of the water, in a little while the _ ' s ' " 

7 The Gills of an 

fish will die. A fish breathes with his Eel * 

gills, and they are made to use the air which is 
in the water. When you take him out of the 
water, his gills get dry, and do not work well. 
He dies for want of air, as we should in the 
water. 

Plants, too, would soon perish, if you could 
take the air entirely from them. 




96 PHYSIOLOGY PRIMER. 

Because air is necessary for us all the time, the 
Creator has given it to us freely. We have to 
work for our food. Even water may be scarce. 
But every one can have as much air as he needs, 
without price. We have only to breathe it. 

3. What is breathing t Drawing the air in, and 
letting it go out, you say. But, if I ask you how 
you draw it in, you might not be able to tell me, 
though it is perfectly easy for you to do it. 

4. When we looked into the chest, we found 
there, besides the heart and the gullet, two lungs, 
one on each side. They are smooth, pinkish 
masses, and not so hard but that you can poke 
your finger through one. You can easily get some 
to examine at the butcher's. He calls them the 
" lights." 

5. The root of each lung is a bundle of tubes, 
which lie close together. These tubes are the 
blood-vessels which go to and from the heart, and 
the air-tube. The air-tubes of the two lungs join, 
in front of the backbone, to form the trachea, or 
ivindpipe. The windpipe is four or five inches 
long, and from half an inch to an inch across. 
If you follow it up through the neck, you find 
that it opens into the throat, and so connects with 
the mouth and nose. 

It is through the mouth and nose that the air is 
drawn in. 



RESPIRATION. 



97 



Larynx. 




Fig. 21. 

Heart and Lungs. 



6. The nose is the true breathing-passage. The 
two openings of the nose we call the nostrils. Be- 
yond these openings are two high and narrow 
passage-ways, which go straight back, and open 
into the throat just above the palate. 

7. There are two reasons why it is better to 
breathe through the nose than through the mouth. 

The first reason is, that the air gets warmed in 
passing through the nose. The passages are nar- 



98 PHYSIOLOGY PRIMER. 

row; and the stream of air is therefore thinner, 
and more easily warmed by the warm walls. 

The second reason is, that the air gets moistened 
in passing through the nose. The walls of these 
narrow passages are lined with a reddish mem- 
brane, like the lining of the mouth. It is both 
warm and moist, and gives its moisture to the thin 
stream of air. 

8. When we breathe through the mouth, the air 
is colder and drier when it reaches the throat. We 
all know how dry the mouth will get when we run, 
and breathe fast through it. People who breathe 
through the mouth all the time are more liable to 
have sore throats. 

9. Whoever has a disease which stops up the 
nose, and prevents his breathing through it, ought 
to have it cured if possible. 

Snoring is caused by breathing through the 
mouth. People who sleep with their mouths 
closed do not snore. 

10. Besides serving us for breathing, the nose 
is the organ of smell. The nerves of smell are in 
the upper part of the nose. Therefore, if we wish 
to smell any thing distinctly, instead of drawing 
the air quietly through in the usual way, we sniff, 
and draw it up. 

11. The food and the air both go into the throat. 



RESPIPiA TIOX. 



99 



There they part company. The food goes down 
the gullet, and the air goes down the windpipe. 
Sometimes we swallow a little air. Sometimes a 
drop of water, or a particle of food, is " swallowed 
the wrong way," and gets into the windpipe. This 
makes us cough furiously until we get it out. But 
generally food and air each takes its own course. 
It is wonderful that they do so. There are nerves 
that keep guard over the entrance to the windpipe, 
and make it open and close at the right time, as 
the switch-tender at the depot 
opens and closes the switches, 
and sends each train on its own 
track. 

12. The upper end of the 
windpipe is a kind of a box. 
You see it in the figure (Fig. 
22), and you can feel it in your 
own neck. It is called "Adam's 
apple." Its sides are made of 
cartilage, which is almost as stiff 
as bone, but not so heavy. This 
box is the larynx, or voice-box, 

13. The vocal cords are tw T o 
elastic cords or bands, which stretch across the 
larynx. They can be tightened or loosened ; and 
they can be spread wide apart, or brought together 




Fig. 22. 

THE LARYNX. — 1 . Adam's 
Apple. 2. Trachea. 



100 PHYSIOLOGY PPIMEB. 

so as to close the passage-way entirely. When we 
wish to make a sound, we make our breath go out 
quickly. As it passes between these cords, it sets 
them in motion, and makes a sound in the same 
way that sound is made in the pipe of an organ 
by the wind which the organ-blower pumps 
through it. If the cords are tight, and near to- 
gether, the tone will be high. If they are loose, 
and wide apart, the tone will be low. 

14. The larynx differs a little in shape and size 
in different people. The vocal cords differ in 
length and thickness. So voices vary, like the 
tones of musical instruments. 

15. The muscles of the larynx grow strong by 
exercise, as other muscles do. By training our 
voices in singing and speaking, they may be made 
stronger and better. 

16. If w r e wish to improve our voices, and learn 
to use them well, we must take pains. Those who 
are careless, and make no effort to speak distinctly 
and correctly, never can do so. 

17. The windpipe has fifteen or twenty rings of 
cartilage in its wall. They are stiff, and keep the 
tube wide open all the time. It is directly in front 
of the gullet. 

It divides into two tubes, which are just like 
itself, which go to the two lungs. Each one when 



RESPIRATION. 



101 



it reaches the lungs divides; and the branches 
divide again, and keep on dividing, until they be- 
come almost as small as hairs ; and then they end 



Bronchial 
tubes. 



—Larynx. 




Fig. 23. 

Section of the Lungs, partly showing the Course of the Bronchial Tubes. 

in little bunches of air-cells. These tubes in the 
lungs are called bronchial tubes. 

18. The air-tubes may be compared to a tree. 
The large tube which goes to the lung is the trunk. 
Just as the trunk divides into limbs, branches, and 
twigs, so the air-tube divides in the lung. The 



102 



PH YSIOLOG Y PllUIER. 



air-cells are like the leaves in which the branches 
end at last. 

19. But the lung is not all air-tubes and air- 
cells. It also contains blood-vessels. The branches 

of the pulmonary artery enter 
it by the side of the air-tube, 
and they divide just as the air- 
tube divides ; and finally the 
little capillaries lie on the out- 
side of the air-cells, forming a 
network over them. If you 
imagine the air-tubes to be 
like a tree, you can imagine 
the blood-vessels to be like 
a vine climbing the tree, and 
following all its limbs and 
branches out to the smallest twigs and the leaves. 
There are some other things in the lungs ; but 
these two — the air-tubes and the blood-vessels — 
are all you need to think of at present. 

20. The air tubes and cells in the lungs always 
contain air. By breathing, we change the air in 
them, and keep it fresh. 

What good does that do us ? Why do we w r ant 
fresh air in them? 

Because we want oxygen. Air is partly made 
of a gas called oxygen. Nothing can live without 




Fig 24. 



Bronchial Tubes and Air -Cells. 



RESPIRATION. 



103 



oxygen. Every bit of our bodies is calling for 
oxygen all the time. So the blood hurries up to 
the lungs, and gets it, and then hurries away to 
distribute it, and then back again for another 
supply, and so on constantly. The air itself does 
not get into the blood, but the oxygen that is 
in the air does. The little capillaries lie on the 
air-cells, and the walls of both capillaries and air- 
cells are thin as a soap- 
bubble. The oxygen passes 
through these walls into the 
blood, as the nourishment 
passes from the alimentary 
canal into the blood. 

21. But we have not yet 
answered the question, 
How do we draw the air 
into the lungs? If you 
take hold of the handles 
of a pair of bellows or of 
an accordion, and pull 
them apart, the air will 
rush in. If you let go the handles, they will grad- 
ually come together, and the air will pour out. 
That is the way the air is made to go into and out 
of the lungs. You remember that the diaphragm 
is a muscle, and can move up and down. When 




104 PHYSIOLOGY PRIMER. 

we take a breath, it moves down, and the sides and 
front of the chest swell out. The diaphragm and 
the walls of the chest pull the elastic lungs with 
them, and stretch them open. Then the air must 
rush in through the air-tubes, and fill them. 

Down and up the diaphragm keeps moving, 
and the breast keeps rising and falling, and the 
breaths of air go in and out as the waves come 
and go on the beach. 

22. The breath which comes out is not so pure 
as the breath which goes in. It has lost part of 
its oxygen ; and it has received from the blood in 
exchange a gas, which we call carbonic-acid gas. 

If many people are in a room, they will soon 
make all the air in it impure by their breathing. 
If no fresh air is let in, there will not be enough 
oxygen after a time to keep them alive. 

23. We do not feel comfortable when we are 
breathing impure air. The room seems close, 
and we feel stifled. We may be sleepy and dull. 
People often suffer from these bad feelings with- 
out knowing what is the cause of them. If they 
would go out of doors, or open their windows, and 
let in the air, they would feel better. 

24. Any bad smell in the air shows that there 
is something in it which ought not to be there. 
It is a sign of danger. 



EFFECT OF ALCOHOL AND TOBACCO. 105 

25, The blood in the veins has a dark purple 
tinge. From the right ventricle of the heart this 
dark blood goes through the pulmonary artery 
to the lungs. When it comes from the lungs 
through the pulmonary veins, it is bright scarlet. 
What has caused this change? It is the oxygen 
that is taken from the air. Besides gaining oxy- 
gen, the blood, while passing through the lungs, 
has lost carbonic-acid gas. 

26. From the left side of the heart the scarlet 
blood is sent all through the body. When it gets 
into the capillaries, it grows dark again. That is 
because it is giving up its load of oxygen. At the 
same time, it takes in from the particles around 
the capillaries, a load of carbonic-acid gas. The 
oxygen is like the fuel that keeps the fire of life 
going, and the carbonic-acid gas is like the ashes. 
So the blood gives fuel, and takes up ashes, and 
carries them to the lungs, where they are thrown 
out in the breath. It is not good to breathe in a 
room full of ashes and smoke. Neither is it good 
to breathe in a room full of carbonic-acid gas from 
the breaths of many people. 

EFFECT OF ALCOHOL AND TOBACCO. 

Sect. II. — 1. Some people think that alcoholic 
drinks prevent consumption. Those who try to 



106 PHYSIOLOGY PRIMER. 

escape it in this way may fall into evils that are 
much worse. 

2. When more than a small amount of alcohol 
is taken, it goes out of the body partly in the 
breath. Habitual drinkers are known by their 
breaths. 

3. Tobacco also clings to the breath, and gives 
it a stale and unpleasant odor. It defiles and 
blackens the teeth. 

4. When tobacco-smoke is drawn down into the 
lungs, it has a more powerful effect than when it 
is puffed directly out of the mouth. The nico- 
tine which it contains passes in greater quantities 
through the delicate walls of the air-cells into the 
blood. 



QUESTIONS. 

Sect. I. — 1. What three things are necessary to maintain life? 
Which can we spare the longest? 

2. Can animals live without air? Can plants? What is the 
most abundant gift of God to us ? 

3. What is breathing ? 

4. What is in the chest? 

5. W 7 hat are the roots of the lungs made of? What is the 
trachea? How long is it? How wide? W r hat does it open into? 

6. What is the true breathing-passage? What are the nostrils ? 
W^hat does the nose open into behind? 

7. What is the first reason named for breathing through the 
nose rather than the mouth? What is the second? 

8. What is the effect of breathing through the mouth? 



QUESTIONS. 107 

9. What is the cause of snoring? 

10. Why do we snuff when we wish to smell keenly? 

11. Why does not food go into the windpipe? 

12. What is the larynx? What is Adam's apple? 

13. What are the vocal cords? How is sound made? 

14. What makes the difference in voices? 

15. Why dees the voice grow strong by exercise? 

16. Can we talk or sing well without effort? 

17. How is the windpipe made? What are the bronchial 
tubes ? 

18. What may the air-tubes be compared to? 

19. What does the lung contain besides air-tubes? What may 
the blood-vessels be compared to? 

20. What do the air tubes and cells contain? Why do we want 
to keep the air in them fresh? What is oxygen? Does air get 
into the blood? How does oxygen get into the blood? 

21. How do we draw the air into the lungs? 

22. How is our breath changed when it comes out? How is 
the air of a room in which are many people changed? 

23. What is the effect of impure air on us? 

24. What does a bad smell indicate? 

25. What is the color of blood in the veins? in the arteries? 
Where does it change from purple to scarlet? What causes the 
change? 

26. Where does it change from scarlet to purple? WTiat causes 
the change? What may oxygen in the body be compared to? 
What may carbonic-acid gas be compared to? 

Sect. II. — 1. Which is worse, consumption or drunkenness? 

2. What effect has alcohol on the breath? 

3. What effect has tobacco on the breath? on the teeth? 

4. Why is tobacco-smoke more injurious when it is breathed 
into the lungs ? 



108 PHYSIOLOGY PRIMER. 



CHAPTER IX. 



THE NERVOUS SYSTEM. —THE EYE.— 
THE EAR 

Sect. I. — 1. When people are tired or ill, they 
sometimes feel nervous. That means that their 
nerves are not in good order. Noises trouble 
them. They are liable to make mistakes, and can 
not thread a needle, or catch a ball, or do other 
easy things, as well as usual. 

Perhaps you have sometime seen in the street a 
large, strong man, who could not walk any better 
than a baby. He reeled and staggered, and finally 
fell as helpless as a sack of meal. If you asked 
what was the matter with him, you were told 
that he had been drinking, and that the drink had 
affected his brain. His muscles were as strong as 
ever, but they would not hold him up because 
his brain was out of order. 

It is evident that the nerves and the brain have 
a good deal to do with the action of our muscles. 

It is time to inquire w T hat the nerves and the 
brain are, and how they act. We shall find that 
they are the most important part of the body. 



THE NERVOUS SYSTEM. 



109 




Fig. 26. 

General Representation of the Nervous System. 



110 PHYSIOLOGY PBIMEB. 

2. You know that the brain is in the skull. 
If you cut through the skull of a dead animal, 
you can take the brain out. It is soft, part white, 
and part gray. The brain of an intelligent ani- 
mal, like a cat or dog, is very much like the brain 
of a man. 

But, with two exceptions, — the whale and the 
elephant, — no animal has as large a brain as man. 

3. We know that it is in the brain that thinking 
is done, and willing, and remembering. For, if a 
man's brain is hurt or diseased, he partly loses the 
power of thinking and willing and remembering. 
If his muscles or his heart or his stomach are 
diseased, it may not affect his mind at all. Be- 
sides, experiments have been made on animals to 
find out what the brain does. These experiments 
show, that, when the brain is taken out, the animal 
does not know any thing. He may have the 
power of moving, but what mind he had is gone. 

Since man can think and remember and know 
so much more than the lower animals, we should 
expect that his brain would be larger, as it is. 

4. From the under part of the brain, a cord 
about as large as your little finger extends down 
like a Chinaman's cue. This cord lies in the cen- 
ter of the backbone, and is called the spinal cord. 
It is soft and cheesy, like the brain, and is part 



THE NERVOUS SYSTEM. Ill 

white, and part gray, in color. The brain and the 
spinal cord are called the nerve-centers. 

5. The brain and the spinal cord are both made 
in halves, which are exactly alike, and are joined 
in the middle. 

6. From each half of the brain, twelve small 




Fig. 27. 

Half of the Brain, and upper end of the Spinal Cord, with the 
Nerves coming from them. 

cords branch off; and from each half of the spinal 
cord, thirty-one small cords branch off. 

These cords are the nerves. Those which come 
from the brain pass through holes in the skull 
to different parts of the head and neck and chest. 
The olfactory nerves lead to the nose, and are 



112 PHYSIOLOGY PRIMER. 

the nerves of smell. The optic nerves lead to the 
eyes, and are the nerves of sight The auditory 
nerves lead to the ears, and are the nerves of hear- 
ing. Others lead to the tongue and the skin and 
other parts. 

7. The nerves from the spinal cord come out 
of the spinal canal in the backbone, and lead to 
all parts of the body below the head. 

8. A nerve is a white and shining cord. The 
sciatic nerve, which is the largest in the body, 
is as much as half an inch wide. The smallest 
nerves can not be seen without a microscope. 

9. If you should follow one of them from the 
backbone, you would find it giving off branches, 
and joining with other nerves, but growing smaller 
the farther you go. At the end it divides up into 
fibers, which reach every bit of the part it sup- 
plies. For example, suppose you start on one 
of the nerves from the neck-part of the spinal 
cord. Directly you find it joining with other 
nerves, and making quite a network. This net- 
work extends down into the armpit. There 
several branches start off, which go to different 
parts of the arm and hand. Follow the one 
which is called the ulnar nerve. That runs down 
the inner side of the arm. When it gets to the 
elbow, it passes just under a point of bone known 



THE NERVOUS SYSTEM. 



113 



as the " funny bone." If you happen to hit this 
point of bone, you are very 
likely to bruise the ulnar 
nerve, and then you have a 
tingling sensation down to 
the end of your little finger. 
The ulnar nerve below the 
elbow lies just in the line of 
this sensation, and it ends in 
the little finger. If you fol- 
lowed it into the skin, you 
would have to use a micro- 
scope; and in that way you 
would see the network that 
it makes. The network is 
so close, that you could not 
prick your finger with a fine 
needle without hurting one 
of the little fibers of it. 

Nearly every part of the 




Fig. 28. 

NERVES OF THE FORE-ARM 
AND HAND. - 1. Artery. 2. 
Nerve. 



body is full of these fine 
nerve-endings. 

10. Now, if you under- 
stand how the nerves are in all parts of the body, 
and how they are all connected with the spinal 
cord or brain, we are ready to inquire what the 
nervous system does. 



114 PHYSIOLOGY PRIMER. 

ACTION OF THE NERVOUS SYSTEM. 

11. If you live in the city, you have often 
looked at the wires of the telegraphs and tele- 
phones over the tops of the houses, — hundreds of 
them running in every direction. And you know 
what they are for. They connect the different 
parts of the city; so that, if a man in his home 
wants to speak to the clerks in his store, he can do 
it, though he is a mile away. If a lady wishes to 
order meat for dinner, she can call the butcher 
without stepping outside her own door. If there 
is danger from burglars, a message goes along the 
wire, and brings a policeman. If there is a fire, it 
calls the engines. And so the people in the city 
can talk together about many things, and help 
each other. 

12. The nervous system is in the body what 
the telegraph system is in the city. The nerves 
are like the wires, and the brain and spinal cord 
are like the offices. 

The different parts of the body must work to- 
gether, and help each other. Suppose the stomach 
wants food. How can it get it unless the hands 
pick it up, and the throat swallows it? When 
the stomach wants food, we feel hungry. That 
is the message that goes through the nerves to the 



ACTION OF THE NERVOUS SYSTEM. 115 

brain, " I am hungry." Then the brain sends 
orders out to the muscles, and they walk us to 
the dinner-table ; and then other muscles pick 
up the food, and others carry it down the throat 
to the stomach. 

Suppose some one has thrown a ball at your 
head. You see it coming. The message goes in 
along the optic nerves to the brain. The brain 
sends out an order to certain muscles, which raise 
the hands to stop it. 

13. Whenever we see or hear or smell or taste 
or touch any thing, a message goes in over the 
nerve of the eye or the ear or the nose or the 
tongue, or the part that is touched, to the spinal 
cord or the brain, and the spinal cord or the brain 
sends out its orders along other nerves. 

14. If a man breaks his back, he may not die 
immediately, but he will not be able to move his 
legs, and he will not feel it if you prick or pinch 
them. He is paralyzed below the place where his 
back is broken. The nerves in the legs connect 
with the spinal cord, and the spinal cord connects 
with the brain. When the back is broken, the 
wires are cut. There is no connection between 
the brain and the legs. The brain may will that 
the legs should move, but it can not send the mes- 
sage down. The legs may be pricked or pinched, 



116 PHYSIOLOGY PRIMER. 

but the brain does not know it. The message 
can not go up. 

15. All our feelings of hunger, thirst, heat or 
cold, or pain or weariness, are carried to the brain 
by the nerves. All our movements are made by 
the action of the nerves. When the nerves and 
brain stop acting, we no longer feel or think or 
move. 

HEALTH OF THE NERVOUS SYSTEM. 

16. Since the brain and nerves have such im- 
portant work to do, we should keep them in good 
condition if possible. 

In order that the brain may be clear, and the 
nerves strong, we need, — 

(i.) Plenty of fresh air. You remember that we 
want air for the sake of the oxygen in it. No part 
of the body has such constant need of oxygen as 
the nervous system. The brain has a great deal 
of blood sent to it ; and, if the blood is cut off 
for an instant, it will stop acting. If there is too 
little oxygen in the air, the brain grows dull, and 
the head feels uncomfortable. 

(5.) We need plenty of exercise. Exercise makes 
us breathe faster, and makes the blood move 
quickly; and so the nerves and brain get more 
oxygen. If we have been sitting still an hour, ten 
minutes of running and jumping makes us feel 



HEALTH OF THE NERVOUS SYSTEM. 117 

brighter. Children need exercise and air more 
than grown people. 

(3.) We need good plain food. The nerves re- 
quire nourishment as well as oxygen. If we do not 
have food enough, or if we spoil our digestion by 
eating too much candy or rich food, the nervous 
system will be starved and weak. 

(4.) We need plenty of sleep. All day the brain 
and nerves are very active. They must rest at 
night, or they will soon wear out. A healthy per- 
son may sit up one night, or even several if he is 
strong ; but it is torture for any one to be deprived 
of sleep for many days. This is because, while we 
are awake, the brain and nerves are wearing out a 
little faster than they are being repaired. In the 
night they are repairing faster than they are wear- 
ing, and by morning they are as good as they were 
the morning before. 

A baby a few days old sleeps almost all the time. 
As he grows older, he sleeps less. Children need 
much more sleep than grown people. Their ner- 
vous systems are more delicate, and wear faster. 
Besides, they are growing, and ought to be a little 
larger and stronger every morning. 

Sitting up late at night makes pale faces and 
weak limbs and irritable nerves. 

(5.) We need change of occupation. Change is 



118 PHYSIOLOGY PRIMER. 

rest. If we have been studying, it rests us to run. 
If we have been playing hard, it rests us to sit 
down with a book. It is not wise for a child to 
read too long at one time. Out of school he 
should be playing, or working in some other way. 

THE EYE. 

Sect. II. — 1. The eyes are placed in two cavi- 
ties called the orbits. The eyeball is a sphere 
about an inch in diameter. It does not fill the 
orbit. There is considerable space around it and 
behind it, which is padded with fatty tissue. This 
makes a cushion for it to rest on. The eyelids, 
with their long lashes, are to protect the eye. The 
eyebrows are a kind of awning, which keeps off 
the perspiration that might trickle down from the 
forehead. 

2. In the orbit, just over the eyeball, is the 
lachrymal gland. This is a gland of about the 
size and shape of an almond. It is filled with 
blood-vessels, and makes tears in the same way in 
which the sweat-glands make perspiration. The 
water comes out of it by little tubes, and flows over 
the surface of the eye. Ordinarily there is just 
enough to keep the eye moist and smooth. 

3. At the inner end of the edge of each eyelid 
is a hole as large as the point of a pin. You can 



THE EYE. 



119 




easily find it on the lower eyelid. These holes are 
the beginnings of little ca- 
nals that carry off the water. 
The canal from the upper, 
and that from the lower lid, 
come together in a sac in 
the inner corner of the or- 
bit, which is called the lach- 
rymal sac. From the lach- 
rymal sac a canal called the 
nasal duct runs straight 
down into the nose. Ordi- 
narily the water can easily 
flow off through these ca- 
nals. We do not notice it 
in the nose. But when we feel badly, or when a 
cold wind blows in our faces, or when we get dust 
in our eyes, the lachrymal glands are very active. 
The water runs into our noses so rapidly that we 
have to use a pocket-handkerchief; and, besides, 
it runs over on our cheeks, making tears. The 
first thing you do, when you cry, is to put your 
knuckles to your eyes to rub the tears out. 

4. We see only the front of the eyeball when it 
is in its place. In the center is a round black 
hole. This is the pupil. The colored part, which 
may be black or brown or blue or gray, is the iris. 



Fig. 29. 

LACHRYMAL APPARATUS.— 
1. Lachrymal gland. 2. Tear-pas- 
sages. 3. Lachrymal sac. 4. Na- 
sal duct. 



120 



PHYSIOLOGY PRIMER. 




1 2 

Fig. 30. 

THE EYE. — 1. Pupil. 2. Iris. 3. Sclerotic 

Coat. 



You notice that the pupil is large when the eye is 
in the shade, and small when it is in a strong 

light. That is because 
the iris, which is made 
in part of muscle-fibers, 
changes its shape. It is 
a curtain with a hole in 
it, and its use is to pro- 
tect the inside of the eye 
from too much light. 
5. If you look from 
the side at the front of an eye, you will see, that, 
before the iris, there is a transparent cover, which 
is like a watch-glass in shape. This is the cronea. 
All around the cornea is the white of the eye. The 
white is the outside coat which covers the whole 
of the ball except the part where the cornea is. It 
is called the sclerotic coat. 

6. Get an ox-eye from the butcher's, and exam- 
ine it. You will see all these things on the front. 
Attached to the sides, you may find, if it has not 
been trimmed off carefully, several slips of red 
muscle. These are the muscles which move the 
ball, and roll it in every direction. At the back 
part, you will find a firm white stem, like the stem 
of a grape. This is the optic nerve, which has 
been cut off in taking the eye out. It comes from 



THE EYE. 



121 



the brain, through a hole in the back part of the 
orbit, and passes through the coats of the ball, and 
then spreads out, and makes a lining for these 
coats. This lining is called the retina. 

7. Now, cut through the ball. It is filled with 
fluid. The ball collapses as a grape would if you 




Fig. 31. 

Eyeball and Optic Nerve. 



should cut it open. If you are careful, you will 
find in it a hard, transparent body shaped like a 
small button. This is the lens. 

8. Now you have seen the principal parts of the 
eyeball. They are, — 



The sclerotic coat. 
The cornea. 
The iris. 



The retina. 

The fluid contents. 

The lens. 



The parts outside the ball are, — 



122 PHYSIOLOGY PRIMER. 

The eyebrows. The lachrymal gland. 

The eyelids. The lachrymal sac. 

The eyelashes. The nasal duct. 

The muscles. The optic nerve. 

9. The eyeball is like the box that the photog- 
rapher uses in taking your picture. In the front 
part of his box there is a lens, as there is in the 
eyeball. In the back part there is a plate, which 
is like the retina; and on this the picture is made. 
When you look at an object, a picture of it is 
made on the retina. The retina is the end of 
the optic nerve. The impression which makes the 
picture is carried by the optic nerve into the brain. 
It is really the brain which sees, not the eye. The 
eye is the instrument. 

10. Good eyes do not often get tired, and they 
see distinctly both far and near objects. Old per- 
sons can not see things near their eyes so dis- 
tinctly as they can see things at a distance. 
Glasses help them to read. Some young persons 
can not see, distinctly, things a little way off, 
though they can see perfectly any thing very 
near their eyes. We call them nearsighted. They 
sometimes have to wear glasses. 

CARE OF THE EYES. 

11. If we do not wish to become near-sighted, 



THE EAR. 



123 



reading when 



or 



feel 



or to have weak eves, we should observe the fol- 
lowing rules: — 

(i.) Do not hold your book too near to your 
eyes. 

(2.) Do not hang your head over your book. 

(5.) Do not read when lying down. 

(4.) Do not read when the light is growing dim. 
Lay down your book until 
lamps are brought. 

(5.) Stop 
your eyes smart 
tired. 

THE EAR. 

Sect. III. — 1. You know 
very well that the ear is not 
all on the outside of the 
head. The part w T hich you 
see is the external ear. It 
is the end of a tube, which 
catches the sounds, and car- 
ries them into the head. 
This tube is an inch long, 
is the tympanum, or drum-head. 

2. The middle ear, or drum, is behind the tym- 
panum. It is a small cavity, which contains the 
little bones of the ear. It is connected with the 
throat by a tube called the Eustachian tube. 




Fig. 32. 

THE EAR. — 1. Parts of the exter- 
nal ear. 2. Parts of the middle 
ear. 3. Parts of the internal ear. 

At the bottom of it 



124 PHYSIOLOGY PRIMER. 

3. The internal ear is still farther in. It is in 
this part of the ear that the nerves of hearing are. 
The external and middle ear carry the sound in. 
The internal ear receives it, and the impression is 
carried from there in to the brain. 

EFFECTS OF ALCOHOL AND TOBACCO. 

Sect. IV. — 1. When men take a little liquor, 
it makes them feel comfortable or gay. The brain 
and nerves are stimulated. If they take enough 
to get slightly intoxicated, they become talkative 
and boastful, or cross or silly. If they drink more, 
they lose their judgment. Their passions become 
violent. They are ready to be excited by small 
things, and to quarrel. Many of the murders and 
other crimes, of which we read every day in the 
papers, are done under the influence of alcohol. 
Men who when sober are quiet and kind, are 
changed by it into wild beasts. After the drunken 
fury is past, they are filled with remorse for what 
they have done. The brain ought to be the mas- 
ter of the whole body. In such men it becomes 
a slave. When the appetite sends in through the 
nerves a demand for liquor, it can not refuse. 

2. The man who indulges freely in drink is 
likely to pay for it the next day. His head aches. 
He is low-spirited and weak. His stomach is foul. 



EFFECTS OF ALCOHOL AND TOBACCO. 125 

His appetite is gone. He then thinks that he 
never will take it again. But, when the nerves 
are accustomed to the excitement of drinking, 
they will not give it up easily. 

3. Delirium tremens is one of the results of the 
free use of alcohol. This is a disease of the ner- 
vous system. The victim of it is wild and raving. 
He is filled with distress and horror. Death some- 
times ends his misery. If he recovers, he is likely 
to have it again if he continues drinking. 

4:. Insanity is another result of drinking-habits. 
Many of the patients in insane-asylums are brought 
there by drink. 

5. Discord in families, quarrels, murders, sick- 
ness, pauperism, insanity, and misery are some of 
the results of the action of alcohol on the nervous 
system. 

Do not understand that alcohol always pro- 
duces such results. Men sometimes use it through 
a long life without seeming to be harmed by it. 
But its victims are in every community, and 
among all classes of the people. 

6. Tobacco acts on the nervous system chiefly. 
At first it makes the head giddy, and the whole 
body faint and sick. Afterwards it gives pleasure. 
An unsteady hand, a languid brain, and an irregu- 
lar heart, often follow its use. Many men are 



126 PHYSIOLOGY PRIMER. 

wearing out their nerves, and shortening their 
lives, by tobacco. Many boys are making their 
bodies puny, and their minds weak, by tobacco. 

Cigarettes are said to have a worse effect on the 
nervous system than cigars. Sometimes they are 
made of the stumps of cigars, which contain more 
nicotine than other tobacco; and their smoke is 
more likely to be drawn into the lungs. 

7. Opium and chloral are used for their effects 
on the nervous system. Their habitual use tends 
to destroy the will-power and the conscience, and 
ruin the mind altogether. 



QUESTIONS. 

Sect. I. — 1. What is it to feel nervous? 

Why does a drunken man fall? 

2, 3. Where is the brain? Of what color is it? What animals 
have the largest brains? Where are thinking, willing, and remem- 
bering done? How do you know? Why should we expect man's 
brain to be larger than the brains of lower animals? 

4-7. What is the spinal cord? Where is it? 'What are the 
nerve-centers? What are the nerves? With what are they all con- 
nected? Where is the olfactory nerve ? the optic nerve? the au- 
ditory nerve? Where do the nerves from the spinal cord go? 

8. How large is the largest nerve? the smallest? 

9. Describe the course of a nerve starting from the backbone. 
Why does your little finger tingle when you strike your " funny- 
bone?" 

11-15. What are telegraph-wires for? How does the nervous 
system resemble the telegraph? Give illustrations. What happens 



QUESTIONS. 127 



when we see or hear or smell or taste or touch any thing? What is 
it to be paralyzed? Could we feel or move without the brain and 
nerves? 

16. Why is fresh air needful for the brain? Why is muscular 
exercise needful for the brain? What happens to the brain and 
nerves if we do not have food enough, or if we spoil our digestion? 

Why is sleep needful for the brain and nerves? 

Why do children need more sleep than grown people? Why 
is change of occupation needful for the brain and nerves? 

Sect. II. — 1-11. What is the cavity in w T hich the eye is situated 
called? What is the lachrymal gland? What is its use? Where 
is the lachrymal sac? Where is the nasal duct? What makes 
tears? What is the pupil of the eye? What is the iris? What is 
its use? What is the cornea? What is the sclerotic coat? What 
do the muscles of the eye do? Where does the optic nerve enter 
the eye? What is the retina? What is contained in the eyeball? 
Name the principal parts of the eyeball. ISTame the principal parts 
of the eye outside of the eyeball. What instrument is the eyeball 
like? For w r hat do old persons need glasses? What is it to be 
"near-sighted "? Give some rules for the care of the eyes. 

Sect. III. — 1-3. What do you call that part of the ear which is 
on the outside of the head? Where is the Eustachian tube? What 
is in the internal ear ? 

Sect. IV. — 1. What is the effect of a small amount of alcohol 
on the nervous system? What is the effect of a larger amount? 
How does alcohol enslave the brain? 

2-4. What is often the effect of the free use of alcohol on 
the nervous system the day after taking it? What diseases of the 
nervous system result from the use of alcohol? 

5. What other results of the action of alcohol on the nervous 
system? Do these results always follow? 

6, 7. What effect does tobacco often have on the nervous sys- 
tem? Are cigarettes less harmful than cigars? What is a common 
effect of the habitual use of opium and chloral? 



Parietal. 



Orbit, 

Inferior Maxillary 

Cervical Vertebras 
Scapula, 



Humerus., — 



Lumbar Vertebras 



Ulna 
Radius 



Carpus. 

Metacarpus, 



Phalanges.— 



Femur., 



Tibia, 

Fibula. 




Temporal. 



Clavicle. 



-Innominate. 



Pelvis. 



Patella. 



Tarsus. 

Metatarsus. 

Phalanges. 



Fig. 33. 



THE FRAMEWORK. 



129 



CHAPTER X. 



THE FRAMEWORK. 



Sect. I. — 1. Thus far we 
have been studying the soft 
parts of the body. When they 
are taken away, the bony frame 
remains. 

A skeleton is a ghastly ob- 
ject. But, if you had no bones 
under your flesh, you could 
not walk, or even stand. The 
skeleton protects the brain 
and the spinal cord, and the 
heart and lungs, and other 
parts, in its cavities. 

2. Man and the quadrupeds, 
and birds and fishes, are all 
alike in this : they all have 
bony frames, and all have 
backbones. The backbone is 
made up of small bones called 
vertebra; and man, and all 
animals with a backbone, are 






CO 



130 



PHYSIOLOGY PRIMER. 



called vertebrates. Their bony frames are a good 
deal alike too. The skeleton of a cat has the 
same parts as that of a man. Her fore-legs corre- 
spond to his arms. Her backbone is lengthened 
out in a tail. Her claws correspond to his finger- 
nails. 

3. A child has many more bones than a man, 
because some bones that were at first separate grow 
together as he gets older. A man has tw T o hundred 
bones. 

4. Some of the bones of the skull are flat. The 
ribs are flat and curved. The hip-bones are very 

irregular in shape. The 
bones of the limbs are 
long and rodlike. 

5. The vertebra which 
make up the backbone 
are bound together by 
strong ligaments. They 
move a little on each 
other; and so the back- 
bone can be bent and 
twisted in every direction, and serves us much 
better than it w r ould if it were all one stiff bone. 
In every vertebra there is a large hole. When 
they are joined together, these holes make a canal 
in the center of the backbone, which is called the 




Fig. 35. 

A VERTEBRA. — 1 . Body. 2. Processes. 
3. Spinal canal. 



THE FRAMEWORK. 



131 



spinal canal. The top vertebra fits around a hole 
in the bottom of the skull. Through this hole, 
the spinal canal connects with the cavity of the 
skull. 

The top vertebra is called the atlas. You can 
easily find the reason for this name by inquiring 
of your teacher. 

6. The spinal cord is well protected by the back- 
bone, and the brain is well protected by the skull. 




Fig. 36. 



THE SKULL. —1. Frontal bone. 2. Parietal bone. 3. Occipital bone. 4. Temporal 
bone. 5. Nasal bone. 6. Malar bone. 7. Superior maxillary bone. 8. Lachrymal 
bone. 9. Inferior maxillary bone. 

The only openings in the skull are the large one 
which connects its cavity with the spinal canal, 
and the small ones which let the nerves through. 

7. The ribs are twelve in number on each side. 
The first seven of these are connected with the 



132 



PHYSIOLOGY PRIMER. 



Shoulder. 



Arm 



backbone behind and the breast-bone in front.* 
These are called true ribs. Five are not connected 
with the breast-bone. They are called false ribs. 

The collar-bone and the 
shoulder-blade form the shoul- 
der. 

The arm (from shoulder to 
elbow) has one bone. 

The fore-arm (from elbow to hand) 
has two bones. 

The hand (including the wrist) has 
twenty-seven bones. 

The two hip-bones are very large 
and strong. The thigh has one bone, 
which is the largest in the body. 

The knee-cap is a small bone in 
front of the knee. 

The leg (from knee to foot) has 
two bones. 
The foot has twenty-six bones. 




Hand, 



Fig. 37. 

The Upper Limb. 



JOINTS. 

Sect. II. — 1. All these bones are connected by 
joints. Some of them are called hinge-joints, be- 
cause they allow movement in two directions, like 
a hinge. The elbow-joint is a hinge-joint. Others 



* For representation of the Thorax, see Fig. 25. 



JOINTS. 



Ui 



Hip... 



Thigh.. 



are called gliding joints, because the bones glide on 
each other in various directions. The wrist-joint 
is a gliding joint. The shoulder and 
the hip joints are called ball-and- 
socket joints. They allow motion in 
every direction, and are the freest of 
all the joints. 

In a movable joint, the bones are 
covered with cartilage (gristle) . Car- 
tilage is smooth, and more elastic 
than bone. It makes the joints 
springy. 

Most of the joints in the skull are 
tight and immovable. 

2. In every machine, the joints 
have to be carefully watched, and 
greased often, or else they will get 
dry, and creak and wear. Our joints 
grease themselves. They have a lin- 
ing, that keeps giving out from its 
surface a fluid like the white of an 
egg. This fluid is called synovia, 
or joint-water. Unless we have rheumatism, or 
some other disease of the joints, they are kept 
always smooth, and in good working-order, in this 
way. 

3. The bones are held together at the joints by 



Foot.. 



Fig. 38. 
Tlie Lower Limb. 



134 



PHYSIOLOGY PRIMER. 




bands of strong, tough substance that does not 
stretch. These bands are called ligaments, and 

they surround the ends 
of the bones. Sometimes 
a bone gets such a twist 
that the end of it breaks 
through the ligaments, 
and gets out of joint 
Then it must be carefully 
put in place. 



STRUCTURE OF BONE. 

Sect. III. — 1. Bones 
that have been thor- 
oughly dried, or that 
have been cooked, are 
white. But a bone in a living person is pink in 
color. It is full of blood-vessels, and has nerves 
too. It is made partly of phosphate of lime, 
which is a mineral just like some rocks. That 
is what gives it its hardness. Children's bones 
are not so brittle as those of grown people. 
They will bend a good deal without breaking. 
The bones of old people are sometimes very 
brittle. 

2. The long bones are not solid, but have a 
canal in their centers. This is filled with marrow. 



Fig. 39. 

JOINTS OP THE SKULL. -1. Frontal 
bone. 2. Parietal bone. 3. Occipital 
bone. 



CARE OF THE FRAME. 



135 



If you cut through a flat bone, you will find that 
it is hard outside, but inside it is full of holes, 
which give it a kind of honeycombed appear- 
ance. 

3. When a bone is broken, it has to be " set." 
In setting bones, the broken ends must be fitted 
together. Bandages, 



and strips of wood, 
or some stiff sub- 
stance, must be put 
around them, to keep 
them in place. Then 
Nature joins them so 
that they are just as 
strong as before. 



CARE OF THE FRAME 



Innominate. 




Femur. 



Fig. 40. 

The Hip -Joint. 



A straight back 



Sect. IV. — 1. Some peo- 
ple have better forms than 
others. The form depends 
chiefly on the bony frame, 
and neck, and a full chest, a waist of natural 
size, and straight limbs, make a good figure. 
The shape we shall have when we are grown 
depends very much on our habits while we are 
children. 

2. If we sit or stand with our shoulders for- 



136 



PHYSIOLOGY PRIMER. 



ward, and our backs curved, we shall be likely to 
have curved backs and stooping shoulders always. 
If we hold up our heads and shoulders, our backs 

will grow straight. 

3. The part of our frames 
which is most frequently 
misshapen is the foot. We 
can change the shape of the 
foot very much by the shoes 
w r e wear. The great toe is 
naturally almost in line with 
the inner side of the foot, 
and the other toes are spread 
out so as to have plenty of 
room. But the great toe of 
most grown people turns in 
toward the other toes, and the toes overlap each 
other. Short and narrow shoes, and high heels, 
have caused this. The swelling on the great-toe 
joint, which is called a bunion, is made in the same 
way. 

4. Tight and high-heeled shoes check the nat- 
ural elastic movements of the foot, and deform it. 
Clothes which bind the waist and chest hinder 
breathing, and squeeze the inward parts out of 




Fig. 41. 
The Shoulder- Joint. 



place. 



The frame should be free in every part to take 



QUESTIONS. 137 




Fig. 42. 

Section of the Thigh-bone. 

the shape which Nature intended for it. Active 
exercise of the muscles helps it to do so. 

EFFECTS OF ALCOHOL AND TOBACCO. 

Sect. V. — 1. The bones are alive as truly as 
are the soft parts of the body. The blood runs 
through them constantly. They depend on it for 
their nourishment and health. When the blood 
is poisoned with alcohol and tobacco, and the rest 
of the system is suffering, the bones must suffer 
too. 

2. There is good reason for believing that boys 
frequently check the growth of their bony frames by 
the use of alcohol and tobacco. 



QUESTIONS. 

Sect. I. — 1. Of what use is the hony frame in the body? 
2. What is a vertebra? What is a vertebrate? What animals, 
with which von are familiar, are vertebrates ? 



138 PHYSIOLOGY PRIMER, 

3, 4. Who has the largest number of bones, — a child or a man ? 
How many bones has a man? What are the shapes of the bones? 

5. What makes the backbone flexible? What makes the spinal 
canal? How does the spinal canal connect with the cavity of the 
skull? Why is the top vertebra called the atlas? 

6. How is the spinal cord protected? The brain? 

7. How many ribs are there? Which are the true ribs? Which 
are the false ribs? With what are the true ribs connected? With 
what are the false ribs connected ? What bones form the shoulder ? 
How many bones in the arm? How many bones in the fore-arm? 
How many bones in the hand? How many bones in the thigh? 
What is the knee-cap? How many bones in the leg? in the foot? 

Sect. II. — 1. How are the bones connected? Name three kinds 
of joints, and mention one of each kind. What joints allow the 
freest motion? What covers the bones, in a movable joint? What 
is the use of this covering? Are all the joints movable? 

2. How are our joints kept smooth ? Do they ever get rough? 

3. What holds the bones together at the joints ? 

Sect. III. — 1. What is the color of bone? Has bone any blood- 
vessels ? What makes bones so hard? What difference is there 
between the bones of children and grown people? 

2, 3. Are the long bones solid? What is in them ? Are the flat 
bones solid? Why not? What must be done with a broken bone ? 
What does Nature do with it? 

Sect. IV. — 1-3. What gives shape to the human form ? What 
do we mean by a good figure ? How may our figures be made better 
or worse? What part of our frames is most often misshapen? 
How is it made so? What is a bunion? 

4. What is the effect of tight and high-heeled shoes? What 
is the effect of tight clothing about the waist and chest? What 
helps the frame to take a good and natural shape? 

Sect. V. — 1. How may alcohol and tobacco affect the bones? 
2* How may they affect the size of the body? 



GLOSSARY AND INDEX. 



GLOSSARY. 



APi-ment. Nourishment. 

A-nat'o-my. The science of the 
structure of organized bodies. 

A-or'ta. The great artery which 
comes from the heart, and passes 
down by the backbone. 

Au'ri-cle. A name given to two 
cavities of the heart. 

Bi'ceps. A muscle on the front of 
the arm. 

Cap'il-la-ry. A hairlike tube. 

Ca-rot'id. A name applied to sev- 
eral arteries in the neck. 

Cor'ne-a. The circular, transparent 
membrane in front of the eye. 

Cor'pus-cle. A minute particle. 

Cu'ti-cle. The upper layer of the 
skin. 

Cu'tis. The deep layer of the skin. 

Dan'drufF. A scurf which forms on 
the scalp, and comes off in small 
scales. 

Di'a-phragm. A sheet made of 
muscle and fibrous membrane, be- 
tween the chest and abdomen. 

En-am'el. The hard and polished 
substance which covers the crown 
of a tooth. 

Gas'tric. Pertaining to the stomach. 

Gland. A name given to many or- 
gans which take part in the pro- 
cesses of life. 

Hy'giene. The science of health. 



I'ris. A colored muscular membrane 

in the anterior chamber of the eye. 
Lach/ry-mal. Pertaining to tears. 
Lymph. Contents of the lymphatic 

vessels. 
Mi'tral. Like a miter, or bishop's 

cap. 
Nar-cot'ic. That which soothes or 

stupefies. 
CE-sdph/a-gus. The gullet. 
Pan'cre-as. An organ of digestion. 

The sweetbread in calves. 
Phys-i-61/o-gy. The science of the 

functions of organized bodies. 
Plas'ma. The watery part of the 

blood. 
Plex'us. A network of vessels, 

nerves, or fibers. 
Pore. The outlet of a sweat duct or 

gland. 
PiiFmo-na-ry. Pertaining to the 

lungs. 
Pu'pil. The central opening in the 

iris. 
Py-lo'rus. A muscular ring which 

surrounds the outlet of the stomach. 
Res-pi-ra/tion. The process of 

breathing. 
Ret'i-na. The terminal fibers of the 

optic nerve, lining the back part of 

the eye. 
Sa-li'va. Spittle. 

Sar-to'ri-fis. A muscle extending 
141 



142 



GLOSSARY. 



from the hip to the leg, on the 

front of the thigh. 
Scle-rot'ic. A term applied to the 

outer coat of the eye. 
Se-ba'ceous. Fatty, or tallowy. 
Sem-i-lu'nar. Shaped like a half- 
moon. 
Sta-pe'di-us. A very small muscle 

in the drum of the ear. 
Stim'u-lant. That which goads or 

excites. 
Syn-o'via. Joint- water. 
Ten'don. A cord of white, fibrous 

tissue connected with a muscle. 
Ten'don of A-chil'les. The tendon 

of the gastrocnemius and soleus 



muscles inserted in the heel. It 
was fabled that this was the only 
part in which Achilles was vul- 
nerable. 

Tho'rax. The chest. 

Tri-chi'na. A small worm that lives 
in the muscles of pigs, and of some 
other animals, and of men. 

Tri-cus'pid. Three-pointed. 

Ven'tri-cle. A name given to sev- 
eral small cavities in the body. 

Ver'te-bra. One of the bones which 
make the backbone, 

Vo'eal cords. Two fibrous bands 
that form the margins of the glot- 
tis, or upper part of the larynx. 



INDEX. 



Abdomen, 76. 
Absorption, 76, 88. 
Adam's apple, 99. 
Air, 95. 
Air-cells, 101. 
Air, impure, 104. 
Alcohol, 72. 

" effects on the skin, 22. 
" effects on muscles, 31. 
" effects on the heart and 

hlood-vessels, 46. 
u effects on the blood, 57. 
" effects on digestive organs, 

90. 
" effects on respiratory or- 
gans, 105. 
" effects on the nervous sys- 
tem, 124. 
" effect on bones, 137. 
Ale, 72. 
Alimentary canal, 77. 

" fluids of, 87. 



divisions of, 87. 



Anatomy, 9. 
Animals, CO. 
Animal food, 61. 
Ankle, 132. 
Aorta, 35, 39. 
Arm, 11, 132. 
Arteries, 35, 38, 46. 
Atlas, 131. 

Backbone, 129. 
Barley, 62. 
Bathing, 20, 57. 



Beans, 63. 

Beef, 24, 61. 

Beer, 72. 

Belly, 76. 

Biceps, 26, 43. 

Bile, 86. 

Blood, 20, 30, 35, 42, 50. 

Blood-vessels, 35, 40, 42, 47. 

Body, parts of, 11. 

Bodily heat, 18. 

Bones, 35, 130. 

" structure of, 134. 
Bowels, 77, 85. 
Brain, 108. 
Brandy, 72. 
Bread, 63. 
Breast-bone, 132. 
Breathing, 96. 
Bronchial tubes, 101. 
Bunion, 136. 
Burn, 12. 

Cake, 64, 89. 

Cancer, 71. 

Candy, 57, 89. 

Capillaries, 35, 39, 40, 46, 55. 

Carbonic-acid gas, 104. 

Carotid artery, 45. 

Cartilage, 99, 133. 

Chest, 76. 

Chloral, 126. 

Cigarettes, 32, 126. 

Circulation, 45. 

Clothing, 19. 

Clots, 31. 

143 



144 



INDEX. 



Coffee, 68. 


Gates, 41. 


Cold, 21. 


Gland, lymphatic, 56. 


Collar-bone, 132. 


Glycogen, 87. 


Cooking, 61, 63. 


Green apples, 90. 


Corn, 62. 


Gullet, 76. 


Corpuscles, 52. 




Cucumbers, 90. 


Hair, 15. 


Cutis, 12. 


Hand, 11, 132. 


Cuticle, 12. 


Headaches, 69. 




Heart, 35, 37, 42. 


Dandruff, 13. 


Hip-bones, 132. 


Delirium tremens, 125. 


Hygiene, 10. 


Diaphragm, 76, 113. 




Digestion, 76, 78. 


Impurity, 58. 


Drinking, 108. 


Insanity, 125. 


Drinking-water, 65. 


Intestines, 77. 


Drum of the ear, 123. 


Intestinal juice, 87. 


Dyspepsia, 89, 91. 


Intoxicating drinks, 65. 




Involuntary muscle, 29. 


Ear, 108, 123. 




Eggs, 62. 


Jaundice, 87. 


Elephant, 110. 


Joints, 132. 


Enamel, 80. 




Eustachian tube, 123. 


Kidneys, 77. 


Exercise, 30, 57, 137. 


Knee-cap, 132. 


Expression, 30. 




Eye, 118. 


Lamb, 61. 


Eyes, care of, 122. 


Larynx, 99. 




Laudanum, 70. 


Fainting, 56. 


Lead pipes, 65. 


Fever, 13, 20. 


Left auricle, 39. 


Fish, 61. 


Leg, 11, 132. 


Flesh, 24, 35. 


Lens, 121. 


Food, 24, 57, 60. 


Ligaments, 134. 


Foot, 11, 132. 


Lights, 96. 


" care of, 136. 


Lips, 79. 


Fore-arm, 11, 132. 


Liver, 76, 86. 


Fowls, 61. 


Lung, 102. 


Frame, care of, 135. 


Lymphatic glands, 56. 


growth of, 137. 


Lymphatics, 50, 55. 


Framework, 129. 






Marrow, 134. 


Gall-bladder, 87. 


Meats, 24. 


Garden vegetables, 63. 


Mineral food, 64. 


Gastric juice, 83. 


Mitral valve, 41. 



INDEX. 



145 



Morphine, 70 


Raw ham, 61. 


Mouth, 77 


Raw sausages, 61. 


Mumps, 82. 


Repair, 53. 


Muscles, 24, 25, 29, 43, 120. 


Respiration, 95. 


Mustard, 67. 


Retina, 121. 


Mutton, 24, 61. 


Ribs, 131. 




Rice, 62. 


Nails, 17. 


Right auricle, 37, 40. 


Narcotics, 22, 60, 67, 69 


Rubbing, 21. 


Nerves, 20, 108, 111. 


Rum, 72. 


Nerve-centers, 111. 


Rye, 62. 


Nervous system, 108. 




Nicotine, 58, 106, 126. 


Saliva, 81, 82. 


Nose, 97. 


Salivary glands, 81. 


Nourishment, 53. 


Salt, 18, 21, 64. 




Sartorius, 26. 


Oatmeal, 62. 


Scar, 12. 


Oats, 62. 


Sciatic nerve, 112. 4 


OEsophagus, 76, 


Sebaceous glands, 16. 


Olfactory nerves, 112. 


Semilunar valves, 41. 


Opium, 69, 126. 


Shoes, tight, 136. 


Optic nerve, 120. 


Shoulder, 132. 


Overflow, 55. 


Shoulder-blade, 132. 


Oxygen, 53, 54, 102. 


Skeleton, 129. 


Oysters, 62. 


Skin, 11, 17, 19, 20, 21. 




Smell, 98. 


Pancreas, 76. 


" bad, 104. 


Pancreatic juice, 87. 


" nerves of, 112. 


Pastry, 64 


Smoker's heart, 48. 


Pease, 63. 


Snoring, 98. 


Pepper, 67. 


Spinal canal, 130. 


Perspiration, 13, 20. 


Spleen, 77. 


Physiology, 9. 


St. Martin, 85. 


Pickles, 57. 


Stapedius, 26. 


Pie, 89. 


Stimulant, 67, 90, 91. 


Plants, 60. 


Stomach, 77, 83, 89, 90, 91. 


Plasma, 52. 


Stomach-glands, 83. 


Pores, 14. 


Sweat, 14. 


Pork, 61. 


Syringe, 44. 


Porter, 72. 


Sweat-glands, 14, 15, 19. 


Potato, 62. 


Sweetbread, 87. 


Pulmonary artery, 38, 112. 


Sweetmeats, 57. 


veins, 39. 


Synovia, 133. 


Pulse, 45. 




Pylorus, 85. 


Tea, 68, 69. 



146 



INDEX. 



Teeth, 79. 






Valves, 41, 


Tendons, 28. 






Valve, tricuspid, 41. 


Tendon of Achilles, 28. 






" semilunar, 41. 


Thigh, 11, 132. 






" mitral, 41. 


Thorax, 76. 






Vegetable food, 62. 


Tongue, 81. 






Vein, 46, 


Tobacco, 10, 58, 70. 






Veins, 35. 


" effect of, on hones 


137. 




Ventricle, 37, 39. 


effects of, on skin, 


22. 




Vertebrae, 129. 


" effects of, on muscles, 32. 


Vertebrates, 130. 


" effects of, on the heart, 


47. 


Vocal cords, 99. 


effects of, on boys, 


71. 




Voice, 95. 


" effects of, on stomach, 


92. 


Voluntary muscle, 29. 


" effects of, on respiratory or- 




gans, 105. 






Walking, 27. 


" effect of, on the breath 


106. 


Waste, 53. 


" effects of, on the 


nervous 


Water, 60, 64. 


system, 124. 






Wear, 53. 


" effects of, on the frame 


137. 


Whale, 110. 


Trachea, 96. 






Wheat, 62. 


Trichina, 61. 






Whisky, 19, 72. 


Tympanum, 123. 






Windpipe, 96, 100. 


Typhoid fever, 66. 






Wines, 71. 
Worms, 16. 


Unripe fruits, 57. 






Wry neck, 12. 



L 'SRARY OF 





m 



